RU2297397C2 - Glass ceramics - Google Patents

Abstract

FIELD: glass ceramics for various industries.

SUBSTANCE: proposed glass ceramics has average hardness no less than 13 GPa and measures x, y and z perpendicular relative one another. Each measure x, y and z is at least 5 mm. Glass ceramics is produced from abrasive particles containing glass ceramics.

EFFECT: improved mechanical properties, hardness and strength.

24 cl, 14 dwg, 7 tbl, 38 ex

Description

A large number of glass and glass-ceramic mixtures are known. In most oxide systems for the manufacture of glass, widely known glass-forming agents are used, such as SiO ₂ , B ₂ O ₃ , P ₂ O ₅ , GeO ₂ , TeO ₂ , As ₂ O ₃ and V ₂ O ₅ , which contribute to the formation of glass. Some of the mixtures obtained using these glass-forming agents can be subjected to heat treatment with the formation of glass ceramics. The upper limit of the operating temperature of glasses and glass ceramics made using these glass former is usually below 1200 ° C; as a rule, it is approximately 700-800 ° C. Glass ceramics, as a rule, have increased heat resistance compared to the glass from which it is made.

In addition, many of the properties of glass and glass ceramics are limited by the properties inherent in glass former. For example, Young's modulus, hardness and strength of glasses and glass ceramics based on SiO ₂ , B ₂ O ₃ and P ₂ O ₅ are limited by similar characteristics of glass former. Such glasses and glass ceramics, as a rule, have poorer mechanical properties than, for example, obtained on the basis of Al ₂ O ₃ or ZrO ₂ . The hardness of known types of glass ceramics is less than 12 GPa. It is desirable to produce glass ceramics with mechanical properties similar to those of Al ₂ O ₃ or ZrO ₂ .

Although some non-traditional glasses and glass ceramics are known, such as rare-earth oxide-alumina glasses (see, for example, PCT application No. WO 01/27046 A1, published April 19, 2001, and Japanese document No. JP 2000-045129, published February 15, 2000), it is also advisable to develop new glasses and glass ceramics, as well as a new application of both known and new glasses and glass ceramics.

On the other hand, various abrasive particles are known in the art (for example, diamond particles, cubic boron nitride particles, fused abrasive particles and sintered ceramic abrasive particles (including abrasive particles obtained by sol-gel technology)). In some grinding methods, abrasive particles are used in free form, while in others, particles are included in abrasive products (for example, coated abrasive products, adhesive abrasive products, non-woven abrasive products, and abrasive brushes). Criteria for selecting abrasive particles for use in a particular grinding method include: wear resistance, shear rate, substrate surface finish, grinding efficiency and cost of the product.

From about 1900 to the mid-1980s. The main abrasive particles used for grinding, for example, using coated abrasive products and with a binder, as a rule, were fused abrasive particles. There are two main types of fused abrasive particles: (1) fused abrasive particles based on alpha alumina (see, for example, U.S. Patent Nos. 1161620 (Coulter), 1192709 (Tone), 1247337 (Saunders et al.), 1268533 (Allen ) and 2424645 (Baumann et al.)) and (2) fused (sometimes also referred to as "fused together") abrasive particles based on aluminum oxide-zirconium (see, for example, US patents Nos. 3891408 (Rowse et al.), 3781172 (Pett et al.), 3893826 (Quinan et al.), 4126429 (Watson), 4457767 (Poon et al.) And 5143522 (Gibson et al.)) (Also see, for example, U.S. Patent Nos. 5023212 ( Dubots et al.) And 5336280 (Dubots et al.), Which describe some of the joint ventures. oxidized nitrous oxide particles). Alumina-based alloyed abrasive particles are usually prepared as follows: an aluminum source, for example, aluminum ore or bauxite, as well as other additives required are loaded into the smelting furnace, the contents are heated to a temperature above the melting point, the melt is cooled to obtain a cured mass, the cured mass crushed to form particles, and then the particles are passed through a sieve and sorted to obtain abrasive particles with a given size distribution. Alumina-zirconia-based fused abrasive particles are usually produced in the same way, except that both an aluminum source and a zirconium source are loaded into the furnace and the melt cools faster than the melt used to produce fused alumina-based abrasive particles . In fused alumina-zirconia abrasive particles, the amount of alumina source is typically about 50-80 wt.%, And the amount of zirconia is 50-20 wt.% Zirconia. A method for producing fused alumina and fused alumina-based abrasive particles may include removing impurities from the melt before the cooling step.

Although fused alpha alumina abrasive particles and fused alumina-zirconia abrasive particles are still widely used for grinding (including grinding with coated abrasive products and with a binder), since about the mid-1980s. For many grinding methods, alpha-alumina-based abrasive particles obtained using sol-gel technology are mainly used (see, for example, US Pat. Nos. 4,314,827 (Leitheiser et al.), 4,518,397 (Leitheiser et al.), 4623364 (Cottringer and others), 4744802 (Schwabel), 4770671 (Monroe and others), 4881951 (Wood and others), 4960441 (Pellow and others), 5139978 (Wood), 5201916 (Berg and others), 5366523 (Rowenhorst and others), 5429647 (Larmie), 5547479 (Conwell and others), 5498269 (Larmie), 5551963 (Larmie) and 5725162 (Garg and others)).

The microstructure of abrasive particles based on alpha-alumina obtained by sol-gel technology can be formed by very small crystals of alpha alumina with or without the addition of auxiliary phases. The service life of abrasive products used for grinding metal, including abrasive particles obtained by sol-gel technology, is much longer than the service life of products obtained using traditional fused abrasive particles based on aluminum oxide.

As a rule, the method for producing abrasive particles obtained by sol-gel technology is more complex and more expensive than the method for producing traditional fused abrasive particles. Typically, the preparation of abrasive particles using a sol-gel technology is carried out as follows: a dispersion or a sol containing water, alumina monohydrate (bomite) and, in another embodiment, a peptizing agent (for example, an acid such as nitric acid) are obtained, gel dispersion, dry gelled dispersion, crush the dried dispersion to obtain particles, sort the particles, selecting particles of the required size, burn the particles to remove volatiles, sinter the calcined particles at a temperature below the melting point alumina and sieved, and sorted, receiving abrasive particles with the desired size distribution. Often sintered abrasive particles include a metal oxide modifier (s) to alter or otherwise modify the physical properties and / or microstructure of the sintered abrasive particles.

Various abrasive products are known in the art. Typically, abrasive articles include a binder and abrasive particles held in the abrasive article by a binder. Examples of abrasive products include coated abrasive products, adhesive abrasive products, nonwoven abrasive products, and abrasive brushes.

Examples of abrasive products with a binder include grinding wheels, cutting wheels and honing stones. The main types of binder systems used to produce abrasive products with a binder include synthetic resin, glass-like materials and metals. In abrasives that include a synthetic resin as a binder, an organic binder system (e.g., phenolic binder system) is used to hold abrasive particles together to form a mass of a particular shape (see, for example, US Pat. Nos. 4,741,743 (Narayanan et al.), 4,800,685 (Haynes et al.), 5037453 (Narayanan et al.) And 5110332 (Narayanan et al.)). Products that include a binder system of a different basic type include ceramic grinding wheels, in which a glass binder is used to bind abrasive particles into a single mass (see, for example, US patents Nos. 4,543,107 (Rue), 4,898,587 (Hay et al.), 4997461 (Markhoff-Matheny et al.) And 5863308 (Qi et al.)). The final formation of the glass binder mass usually occurs at a temperature of from 900 to 1300 ° C. Today, to obtain ceramic grinding wheels, abrasive particles are used both on the basis of fused alumina and those obtained by sol-gel technology. However, fused alumina-zirconia is generally not included in ceramic bonded grinding wheels due in part to the thermal stability of alumina-zirconia. At an elevated temperature at which a glass binder mass is formed, the physical properties of alumina-zirconium oxide deteriorate, leading to a significant decrease in grinding quality. In metal binder abrasive products, sintered or galvanized metal is typically used to bond abrasive particles.

The production of abrasives still needs abrasive particles and abrasive products with a simpler and cheaper method of production and / or with better performance than conventional abrasive particles and products.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides glass ceramics with an average hardness of at least 13 GPa (in some embodiments, preferably at least 14, 15, 16, 17, or even at least 18 GPa), wherein the glass ceramics are perpendicular to each other the other measures x, y and z, and also where each of the dimensions x, y and z is at least 5 mm (in some embodiments, implementation of the present invention at least 10 mm). The dimensions of the material x, y and z are determined either visually or using a microscope, depending on their size. The indicated size z represents, for example, the diameter of the sphere, the thickness of the coating or the maximum length of the prismatic shape.

In this application:

the term "amorphous material" means a material obtained from a melt and / or vapor phase, which does not have a long-range crystalline structure according to x-ray diffraction measurements and / or gives an exothermic peak for crystallization of amorphous material in DTA (differential thermal analysis) diagrams in the analysis indicated in this text in a similar way;

the term "ceramics" covers amorphous materials, glass, crystalline ceramics, glass ceramics, and combinations thereof;

the term "complex metal oxide" refers to a metal oxide comprising two or more metals and oxygen (for example, CeAl ₁₁ O ₁₈ , Dy ₃ Al ₅ O ₁₂ , MgAl ₂ O ₄ and Y ₃ Al ₅ O ₁₂ );

the term "Al ₂ O ₃ metal oxide complex" refers to a metal oxide complex comprising, based on theoretical studies of Al ₂ O ₃ oxides, and one or more metals other than Al (for example, CeAl ₁₁ O ₁₈ , Dy ₃ Al ₅ O ₁₂ , MgAl ₂ O ₄ and Y ₃ Al ₅ O ₁₂ );

the term "Al ₂ O ₃ -Y ₂ O ₃ complex" refers to a metal oxide complex including, based on theoretical studies of Al ₂ O ₃ and Y ₂ O ₃ oxides (for example, Y ₃ Al ₅ O ₁₂ );

the term "Al ₂ O ₃ -REO complex" refers to a metal oxide complex comprising, based on theoretical studies, Al ₂ O ₃ oxides and a rare earth metal oxide (for example, CeAl ₁₁ O ₁₈ and Dy ₃ Al ₅ O ₁₂ );

the term "glass" refers to an amorphous material having a glass transition temperature;

the term "glass ceramic" refers to ceramics containing crystals formed by heat treatment of an amorphous material;

"T _g " means the glass transition temperature determined by the method described herein under the name "differential thermal analysis";

"T _x " means the crystallization temperature determined by the method described herein under the name "differential thermal analysis";

the term “rare earth oxides” includes cerium oxide (eg CeO ₂ ), dysprosium oxide (eg Dy ₂ O ₃ ), erbium oxide (eg Er ₂ O ₃ ), europium oxide (eg Eu ₂ O ₃ ), oxide gadolinium (e.g. Gd ₂ O ₃ ), holmium oxide (e.g. Ho ₂ O ₃ ), lanthanum oxide (e.g. La ₂ O ₃ ), lutetium oxide (e.g. Lu ₂ O ₃ ), neodymium oxide (e.g. Nd ₂ O ₃ ), praseodymium oxide (e.g. Pr ₆ O ₁₁ ), samarium oxide (e.g. Sm ₂ O ₃ ), terbium oxide (e.g. Tb ₂ O ₃ ), thorium oxide (e.g. Th ₄ O ₇ ), thulium oxide (for example, Tm ₂ O ₃ ), ytterbium oxide (for example, Y ₂ O ₃ ) and combinations thereof; and

the term "REO" refers to rare earth oxide (s).

It is assumed in this text that if it is not indicated that a metal oxide (for example, Al ₂ O ₃ , a complex of Al ₂ O ₃ metal oxide, etc.) is a crystalline component, for example, in glass ceramics, then it should be understood so that this oxide may be in an amorphous state, a crystalline state, or partially in an amorphous and partially in a crystalline state. For example, if glass ceramics contains Al ₂ O ₃ and ZrO ₂ , then both Al ₂ O ₃ and ZrO ₂ can each be in an amorphous state, crystalline state, or partially in an amorphous and partially crystalline state, or as a reaction product with an oxide (oxides ) other (other) metal (s) (for example, if it is not indicated that, for example, Al ₂ O _{3 is} present in the form of crystalline Al ₂ O ₃ or a special crystalline phase Al ₂ O ₃ (for example, alpha-Al ₂ O ₃ ) , it may be present as crystalline Al ₂ O ₃ and / or as part of one or more complex crista complexes-crystal Al ₂ O ₃ -oxides metals.

Further, it should be understood that the glass ceramics obtained by heating an amorphous material and not characterized by T _g may not actually contain glass, but may consist of crystals and an amorphous material that does not have T _g .

In some embodiments, implementation of the present invention, the preferred glass ceramics in accordance with the present invention contains at least 35 (in some embodiments, the implementation of the present invention preferably at least 40, 45, 50, 55, 60, 65, or even at least 70) wt.% Al ₂ About ₃ in relation to the total mass of glass ceramics. In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, as well as glasses used to produce glass ceramics, in addition to Al ₂ O ₃ , contain other oxides such as Y ₂ O ₃ , REO, ZrO ₂ , HfO ₂ and / or their combinations.

In some embodiments of the present invention, the preferred glass ceramics of the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , Y ₂ O ₃ and at least one of ZrO ₂ or HfO ₂ oxides, wherein Al ₂ O _3, Y ₂ O ₃ and at least one of the oxides ZrO _2, or HfO ₂ together represent at least 80 wt.% based on the total weight of the glass or glass-ceramic. In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , REO and at least one of ZrO ₂ or HfO ₂ oxides, where Al ₂ About ₃ , REO and at least one of the oxides of ZrO ₂ or HfO ₂ together comprise at least 80 (in some embodiments, 85, 90, 95, or even at least 100) wt.% in relation to total weight of glass or glass omy. In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , REO, Y ₂ O ₃ and at least one of ZrO oxides ₂ or HfO ₂ , where Al ₂ O ₃ , REO, Y ₂ O ₃ , and at least one of the ZrO ₂ or HfO ₂ oxides together comprise at least 80 (in some embodiments, 85, 90, 95, or even at least 100) wt.% in relation to the total weight of the glass sludge glass ceramics.

In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , REO and at least one of ZrO ₂ or HfO ₂ oxides, where Al ₂ O ₃ , REO, and at least one of the ZrO ₂ or HfO ₂ oxides together are at least 60 (in some embodiments, 65, 70, 75, 80, 85, 90, 95, or even at least 100) wt.%, SiO ₂ is less than 20 (in some Var antah of the present invention is preferably at least 15, 10, 5, or even zero) wt.% and B ₂ O ₃ is less than 20 (in some embodiments, preferably at least 15, 10, 5, or even zero) wt.% with respect to the total mass of glass or glass ceramics. In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , Y ₂ O ₃ and at least one of ZrO ₂ or HfO ₂ , where Al ₂ O ₃ , Y ₂ O ₃ and at least one of the ZrO ₂ or HfO ₂ oxides together comprise at least 60 (in some embodiments, 65, 70, 75, 80, 85, 90, 95 or even at least 100) wt.%, SiO ₂ is less than 20 (in some embodiments of the present invention preferably less than 15, 10, 5 or even zero) wt.% and BrO ₃ is less than 20 (in some embodiments of the present invention preferably less than 15, 10, 5 or even zero) wt.% in relation to the total weight glass or glass ceramics. In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , Y ₂ O ₃ , REO and at least one of ZrO oxides ₂ or HfO ₂ , where Al ₂ O ₃ , Y ₂ O ₃ , REO and at least one of the ZrO ₂ or HfO ₂ oxides together comprise at least 60 (in some embodiments, 65, 70, 75, 80, 85, 90, 95, or even at least 100) wt.%, SiO ₂ is less than 20 (in not which embodiments of the present invention are preferably less than 15, 10, 5 or even zero) wt.% and B ₂ O ₃ is less than 20 (in some embodiments of the present invention, preferably less than 15, 10, 5 or even zero) wt.% in relation to the total mass of glass or glass ceramics.

In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , Y ₂ O ₃ and at least one of ZrO ₂ or HfO ₂ , where Al ₂ O ₃ , Y ₂ O ₃ and at least one of the ZrO ₂ or HfO ₂ oxides together comprise at least 60 (in some embodiments, 65, 70, 75, 80, 85, 90, 95 or even at least 100) wt.% In relation to the mass of glass and st klokeramike, a SiO _2, B ₂ O ₃ and P ₂ O ₅ together make up at least 40 (in some embodiments, preferably at least 35, 30, 25, 20, 15, 10, 5, or even zero) wt.% based on to the total mass of glass or glass ceramics. In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , REO and at least one of ZrO ₂ or HfO oxides ₂ , where Al ₂ O ₃ , REO, and at least one of the ZrO ₂ or HfO ₂ oxides together are at least 60 (in some embodiments, 65, 70, 75, 80, 85, 90, 95, or even at least 100) wt.% with respect to the weight of glass and glass ceramics, a SiO ₂ , B ₂ O ₃ and P ₂ O ₅ together comprise less than 40 (in some embodiments, preferably less than 35, 30, 25, 20, 15, 10, 5, or even zero) wt.% with respect to to the total mass of glass or glass ceramics. In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain Al ₂ O ₃ , REO, Y ₂ O ₃ and at least one of ZrO ₂ or HfO ₂ oxides, where Al ₂ O ₃ , REO, Y ₂ O ₃ and at least one of the ZrO ₂ or HfO ₂ oxides together comprise at least 60 (in some embodiments, 65, 70, 75, 80, 85, 90, 95 or even at least 100) wt.% In relation to the weight of the glass and glass ceramics, a SiO ₂ , B ₂ O ₃ and P ₂ O ₅ together comprise less than 40 (in some embodiments, preferably less than 35, 30, 25, 20, 15, 10, 5, or even zero)% wt. in relation to the total weight of glass or glass ceramics.

In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain a total of less than 40 (in some embodiments of the present invention, preferably less than 35, 30, 25, 20 , 15, 10, 5 or even zero) wt.% SiO ₂ , B ₂ O ₃ and P ₂ O ₅ with respect to the total weight of glass or glass ceramics. In some embodiments of the present invention, the preferred glass ceramics in accordance with the present invention, glasses including such glass ceramics, as well as glasses used to make such glass ceramics, contain a total of not more than 10 (in some embodiments, the implementation of the present invention is preferably less than 5, 4, 3, 2, 1 or even zero) wt.% As ₂ O ₃ , B ₂ O ₃ , GeO ₂ , P ₂ O ₅ , SiO ₂ , TeO ₂ and V ₂ O ₅ with respect to the total weight of glass or glass ceramics.

In some embodiments, implementation of the present invention, the glass ceramic preferably contains at least 35, 40, 45, 50, 55, 60, 65, or even at least 70 wt.% Al ₂ O ₃ relative to the total weight of the glass ceramics.

In another aspect, the present invention provides a method for producing glass ceramics in accordance with the present invention, which includes:

heat treatment of an amorphous material (eg glass), as a result of which at least a portion of the amorphous material is converted to glass ceramics in accordance with the present invention.

In another aspect, the present invention provides a method for producing a glass ceramic product, which comprises:

obtaining particles of glass characterized by T _g ;

heating the glass particles to a temperature exceeding T _g so that as a result the glass particles coalesce to form a certain shape;

cooling the mold to produce a glass product; and heat treating the glass product to produce a glass ceramic product.

In a further aspect, the present invention provides abrasive particles comprising glass ceramics in accordance with the present invention with an average hardness of at least 15 GPa, preferably at least 16 GPa, at least 17 GPa, or even at least 18 GPa.

Abrasive particles can be used as part of an abrasive product or in an unbound form. Abrasive particles in accordance with the present invention include a binder and a set of abrasive particles, where at least part of the set of abrasive particles are abrasive particles in accordance with the present invention. Examples of abrasive products include coated abrasive products, bonded abrasive products (e.g. circles), non-woven abrasive products, and abrasive brushes. Coated abrasive particles typically include a base comprising first and second opposing main surfaces, where a binder and a combination of abrasive particles form an abrasive layer on at least a portion of the first main surface.

In some embodiments of the present invention, the abrasive particles in accordance with the present invention preferably comprise at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 in the abrasive article. , 80, 85, 90, 95, or even 100 wt.% With respect to the total mass of the aggregate of abrasive particles contained in the abrasive product.

Before use, abrasive particles are usually sorted to obtain a given size distribution. Such a distribution is usually in the range of particle sizes from coarse to fine. In the field of abrasive technology, fractions within a given interval are sometimes referred to as “coarse”, “control” and “fine”. Abrasive particles, sorted in accordance with industry-accepted classification standards, have a size distribution corresponding to a nominal discharge with certain numerical limits. Such industry-accepted classification standards (i.e., certain nominal ranks) include American National Institute of Standards (ANSI), European Federation of Abrasive Product Manufacturers (FEPA) standards, and Japanese Industrial Standards (JIS). In one aspect, the present invention provides a plurality of abrasive particles of a particular nominal discharge, wherein at least a portion of the plurality of abrasive particles are abrasive particles in accordance with the present invention. In some embodiments, implementation of the present invention, the abrasive particles in accordance with the present invention are preferably at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or even 100 wt.% With respect to the total mass of the aggregate of abrasive particles contained in the abrasive product in accordance with the present invention, based on the total mass of the plurality of abrasive particles.

In another aspect, the present invention provides a method for producing abrasive particles in accordance with the present invention, comprising heat treating the particles containing amorphous material, by which at least a portion of the amorphous material is converted to glass ceramics to form abrasive particles. Typically, abrasive particles, including glass ceramics, sorted after heat treatment, obtaining a set of abrasive particles of a specific nominal discharge, where at least part of the collection of abrasive particles is a collection of abrasive particles, including glass ceramics. In one embodiment, before heat treating the particles containing the amorphous material, a collection of particles of a particular nominal discharge is obtained, where at least a portion of the particles is a collection of particles containing amorphous material to be heat treated, and where the heat treatment is carried out so as to obtain a combination of abrasive particles specific nominal discharge, where at least part of the abrasive particles is a collection of abrasive particles containing glass ceramics.

In another aspect, the present invention provides a method for producing abrasive particles in accordance with the present invention, comprising heat treating the particles containing amorphous material, by which at least a portion of the amorphous material is converted to glass ceramics to form abrasive particles. Typically, abrasive particles, including glass ceramics, sorted after heat treatment, obtaining a set of abrasive particles of a specific nominal discharge, where at least part of the collection of abrasive particles is a collection of abrasive particles, including glass ceramics. Optionally, before heat treating the particles containing the amorphous material, an aggregate of particles of a particular nominal discharge is obtained, where at least a portion of the particles is an aggregate of particles containing amorphous material to be heat treated, and where the heat treatment is carried out so as to obtain a population of abrasive particles of a particular nominal discharge where at least a portion of the abrasive particles is a collection of abrasive particles containing glass ceramics.

In another aspect, the present invention provides a method for producing abrasive particles in accordance with the present invention, which includes:

heat treatment of the amorphous material, as a result of which at least a portion of the amorphous material is converted to glass ceramics in accordance with the present invention with an average hardness of at least 15 GPa; and

grinding glass ceramics to obtain abrasive particles, including glass ceramics. Typically, abrasive particles, including glass ceramics, sorted, obtaining a set of abrasive particles of a particular nominal discharge, where at least part of the collection of abrasive particles is a collection of abrasive particles comprising glass ceramics.

In a further aspect, the present invention provides a method for grinding a surface, the method comprising:

obtaining an abrasive product comprising a binder and a combination of abrasive particles, which are at least partially abrasive particles in accordance with the present invention;

bringing into contact at least one of the abrasive particles in accordance with the present invention with the surface of the workpiece; and

the movement of at least one of the contacted abrasive particles in accordance with the present invention and the contact surface, resulting in grinding of at least a portion of the surface with an abrasive particle in accordance with the present invention in contact with this surface.

In another aspect, the present invention provides a method for producing glass ceramics in accordance with the present invention, which includes:

the combination of at least (a) Tg glass and (b) heat-resistant particles (e.g., metal oxide particles, boride particles, carbide particles, nitride particles, diamond particles, metal particles, glass particles, and combinations thereof) particles;

heating the glass particles to a temperature exceeding T _g so that as a result the glass particles coalesce to form a specific shape;

glass cooling to obtain ceramics; and

heat treatment of glass ceramics, as a result of which at least part of the glass turns into glass ceramics.

Glass ceramics in accordance with the present invention can be obtained in the form of particles (for example, glass beads (for example, balls having a diameter of at least 1 micrometer, 5 micrometers, 10 micrometers, 25 micrometers, 50 micrometers, 100 micrometers, 150 micrometers, 250 micrometers, 500 micrometers, 750 micrometers, 1 mm, 5 mm or even at least 10 mm), products (for example, plates), fibers, particles and coatings (for example, thin coatings)) or turned into such particles, products, fibers and coatings . Particles and fibers made of glass ceramics are used, for example, for thermal insulation, and also as fillers or reinforcing substances in composites (for example, in ceramic composites, metal composites or in composites based on a polymer matrix). Thin coatings can be used, for example, as protective coatings for applications involving abrasion, as well as for heat regulation. Examples of products that can be obtained in accordance with the present invention include kitchen utensils (e.g., plates, knives), dental braces and reinforcing fibers, cutting tool inserts, abrasives and structural components of gas engines (e.g., valves and bearings), medical implants and surgical scalpels. Other products include those that have a ceramic coating on the outer surface of the housing or on another surface.

Brief Description of the Drawings

Figure 1 schematically shows a fragment of a cross section of a coated abrasive product comprising abrasive particles in accordance with the present invention;

figure 2 shows a three-dimensional image of an abrasive product with a binder comprising abrasive particles in accordance with the present invention;

figure 3 shows an enlarged schematic illustration of an abrasive product on a non-woven basis, including abrasive particles in accordance with the present invention;

figure 4 shows the results of the DTA of the material obtained in example 1;

figure 5 shows a raster-electron micrograph (SEM-Scanning Electron Micrograph) of the fracture surface of the material obtained in example 22;

figure 6 shows a raster electron micrograph (SEM) of the fracture surface of the material obtained in example 24;

7 shows a raster electron micrograph (SEM) of the fracture surface of the material obtained in example 30;

on Fig shows a raster electron micrograph (SEM) of the fracture surface of the material obtained in example 30;

figure 9 shows a raster electron micrograph (SEM) of the fracture surface of the material obtained in example 31;

figure 10 shows a micrograph of the material obtained using an electron microscope with backscattering obtained in example 32;

figure 11 shows an optical micrograph of a slice (2 mm thick) of the material obtained by hot pressing, showing the transparency of the material;

on Fig shows a raster electron micrograph (SEM) of the polished portion of the material of example 35 obtained using heat treatment; and

13 and 14 show raster electron micrographs (SEM) of the polished sections of the materials of examples 36 and 37, respectively, obtained using heat treatment.

Detailed description

Glass ceramics in accordance with the present invention can be obtained, for example, by incorporating crystalline amorphous material (eg glass) or an amorphous material in a ceramic containing amorphous material. In some embodiments, implementation of the present invention, the amorphous material used to produce glass ceramics in accordance with the present invention, and the resulting glass ceramics preferably contain a total of not more than 30 (in some embodiments, the implementation of the present invention preferably not more than 20, 15, 10, 5, 4, 3, 2, 1 or even zero) wt.% As ₂ O ₃ , B ₂ O ₃ , GeO ₂ , P ₂ O ₅ , SiO ₂ , TeO ₂ and V ₂ O ₅ with respect to the total mass of the amorphous material or glass ceramics.

In some embodiments, implementation of the present invention, the amorphous material used to produce glass ceramics in accordance with the present invention, and the resulting glass ceramics preferably contain at least 35, 40, 45, 50, 55, 60, 65, or even 70 wt.% Al ₂ About ₃ in relation to the total mass of amorphous material or glass ceramics.

Some amorphous materials used to produce glass ceramics in accordance with the present invention, and glass ceramics obtained from them contain from 20 to at least 70 wt.% (In some embodiments, implementation of the present invention from 30 to at least 70%, from 40 to at least 70%, from 50 to at least 70%, or even from 60 to at least 70%) Al ₂ O ₃ ; from 0 to 50 wt.% (in some embodiments, implementation of the present invention from 0 to 25%; or even from 0 to 10%) Y ₂ O ₃ ; and from 0 to 70 wt.% (in some embodiments, implementation of the present invention from 0 to 50%; from 0 to 25% or even from 0 to 10%) of at least one of ZrO ₂ or HfO ₂ relative to the total mass of amorphous material or glass ceramics. In some embodiments, implementation of the present invention, such amorphous materials and glass ceramics obtained from them contain at least 30 wt.%, At least 40 wt.%, At least 50 wt.%, At least 60 wt.% Or even at least at least 70 wt.% Al ₂ About ₃ in relation to the total weight of the amorphous material or glass ceramics. In some embodiments of the present invention, such amorphous materials and glass ceramics obtained therefrom contain less than 40 in total (in some embodiments, less than 35, 30, 25, 20, 15, 10, 5, 4, 3, 2, 1, or even zero) wt.% SiO ₂ , B ₂ O ₃ and P ₂ O ₅ with respect to the total mass of amorphous material or glass ceramics. In some embodiments, implementation of the present invention, such amorphous materials and glass ceramics obtained from them contain a total of less than 20 (in some embodiments, implementation of the present invention less than 15, 10, 5 or even zero) wt.% SiO ₂ and less than 20 (preferably less than 15, 10, 5 or even zero) wt.% In ₂ O ₃ in relation to the total mass of amorphous material or glass ceramics.

Some amorphous materials used to produce glass ceramics in accordance with the present invention, and glass ceramics obtained from them contain from 20 to at least 70 wt.% (In some embodiments, implementation of the present invention from 30 to at least 70%, from 40 to at least 70%, from 50 to at least 70%, or even from 60 to at least 70%) Al ₂ O ₃ ; from 0 to 70 wt.% (in some embodiments, implementation of the present invention from 0 to 50%; from 0 to 25%; or even from 0 to 10%) REO; from 0 to 50 wt.% (in some embodiments, implementation from the present invention from 0 to 25% or even from 0 to 10%) of at least one of ZrO ₂ or HfO ₂ in relation to the total weight of the amorphous material or glass ceramic. In some embodiments, the implementation of the present invention, such amorphous materials and glass ceramics obtained from them contain 30 wt.%, At least 40 wt.%, At least 50 wt.%, At least 60 wt.% Or even at least 70 wt. .% Al ₂ About ₃ in relation to the total mass of amorphous material or glass ceramics. In some embodiments, implementation of the present invention, such amorphous materials and glass ceramics obtained from them contain a total of less than 40 (in some embodiments, implementation of the present invention less than 35, 30, 25, 20, 15, 10, 5, 4, 3, 2, 1 or even zero) wt.% SiO ₂ , B ₂ O ₃ and P ₂ O ₅ with respect to the total mass of amorphous material or glass ceramics. In some embodiments, implementation of the present invention, such glasses and glass ceramics obtained from them contain a total of less than 20 (in some embodiments, implementation of the present invention less than 15, 10, 5 or even zero) wt.% SiO ₂ and less than 20 (in some embodiments, implementation of the present inventions of less than 15, 10, 5 or even zero) wt.% In ₂ O ₃ in relation to the total mass of amorphous material or glass ceramics.

Some amorphous materials used to produce glass ceramics in accordance with the present invention, and glass ceramics obtained from them contain from 20 to at least 70 wt.% (In some embodiments, implementation of the present invention from 30 to at least 70%, from 40 to at least 70%, from 50 to at least 70%, or even from 60 to at least 70%) Al ₂ O ₃ ; from 0 to 70 wt.% (in some embodiments, implementation of the present invention from 0 to 50%; from 0 to 25%; or even from 0 to 10%) Y ₂ About ₃ ; from 0 to 70 wt.% (in some embodiments, implementation of the present invention from 0 to 50%; from 0 to 25%; or even from 0 to 10%) REO; from 0 to 50 wt.% (in some embodiments, implementation from the present invention from 0 to 25% or even from 0 to 10%) of at least one of ZrO ₂ or HfO ₂ in relation to the total weight of the amorphous material or glass ceramic. In some embodiments, implementation of the present invention, such amorphous materials and glass ceramics obtained from them contain at least 30 wt.%, At least 40 wt.%, At least 50 wt.%, At least 60 wt.% Or even at least at least 70 wt.% Al ₂ About ₃ in relation to the total weight of the amorphous material or glass ceramics. In some embodiments, implementation of the present invention, such amorphous materials and glass ceramics obtained from them contain a total of less than 40 (in some embodiments, implementation of the present invention less than 35, 30, 25, 20, 15, 10, 5, 4, 3, 2, 1 or even zero) wt.% SiO ₂ , B ₂ O ₃ and P ₂ O ₅ with respect to the total mass of amorphous material or glass ceramics. In some embodiments, implementation of the present invention, such amorphous materials and glass ceramics obtained from them contain a total of less than 20 (in some embodiments, implementation of the present invention less than 15, 10, 5 or even zero) wt.% SiO ₂ and less than 20 (in some embodiments, implementation less than 15, 10, 5, or even zero) wt.% B ₂ O ₃ in relation to the total weight of the amorphous material or glass ceramic.

Amorphous materials (e.g. glass), ceramics containing an amorphous substance, particles containing an amorphous material, etc. can be obtained, for example, by heating (including in a flame) an appropriate source of metal oxide to form a melt, preferably a homogeneous melt, and then rapidly cooling the melt to form an amorphous material. Variants of the amorphous material can be obtained, for example, by melting the sources of metal oxides in any suitable melting furnace (for example, in an induction heating furnace, in a gas furnace or in an electric furnace) or, for example, in plasma. The resulting melt is cooled (for example, using a cooling medium (such as high-speed jets of air, liquids, metal plates (including chilled metal plates), metal rolls (including chilled metal rolls), metal balls (including chilled metal balls), etc. .)).

Variants of the amorphous material can be obtained by crystallization in flame, as described, for example, in US patent No. 6254981 (Castle). In this method, sources of metal oxides are placed (for example, in the form of particles, sometimes called "starting particles") directly into the combustion zone (for example, a methane-air burner, an acetylene-oxygen burner, a hydrogen-oxygen burner, etc.) and then extinguish, for example, with water, cooling oil, air, etc. The starting particles can be obtained, for example, by crushing, agglomeration (eg, spraying and curing), melting or sintering of metal oxide sources. The size of the initial particles supplied to the flame, as a rule, determines the size of the resulting particles containing amorphous material.

Variants of the amorphous material can also be obtained using other methods, such as drawing a melt obtained by laser action into a filament with free-fall cooling, obtaining a wire by the Taylor method, a plasmatron method, a hammer and anvil method, centrifugal quenching, spray cooling using a spray apparatus, blanking with rotation on a single and double roller, blanking on a plate on rollers and drip release of the melt (see, for example, Rapid Solidification of Ceramics (Accelerated curing of ceramics), Brockway et al., Metals And Ceramics Information Center, A Department of Defense Information Analysis Center, Columbus, Ohio, January 1984). Variants of the amorphous material can also be obtained using other methods, such as thermal pyrolysis (including flame pyrolysis, laser or plasma pyrolysis) of suitable previously used methods, vapor-phase synthesis of previously used metallic materials, and mechanochemical processing.

Used compositions containing amorphous materials include eutectic compositions or close to them (for example, double or triple eutectic compositions). After familiarization with the present description, a person skilled in the art will understand that in addition to the compositions described herein, other eutectic compositions can be used, including quaternary and higher orders.

As a rule, amorphous materials and the glass ceramics obtained from them in accordance with the present invention have perpendicular to each other dimensions x, y and z, where each of the dimensions x, y and z is at least 25 micrometers. In some embodiments, x, y, and z are at least 30 micrometers, 35 micrometers, 40 micrometers, 45 micrometers, 50 micrometers, 75 micrometers, 100 micrometers, 150 micrometers, 200 micrometers, 250 micrometers, 500 micrometers, 1000 micrometers, 2000 micrometers, 2500 micrometers, 1 mm, 5 mm or even at least 10 mm.

Sources of Al ₂ O ₃ (based on theoretical studies of oxides), including marketed sources, include bauxite (including natural bauxite and synthetic bauxite), calcined bauxite, hydrated aluminum oxides (e.g. bomite and gibbsite), aluminum, Bayer alumina, aluminum ore, gamma alumina, alpha alumina, aluminum salts, aluminum nitrates, and combinations thereof. The source of Al ₂ O ₃ may contain Al ₂ O ₃ or may be only a raw material for producing Al ₂ O ₃ . Alternatively, the source of Al ₂ O ₃ may contain Al ₂ O ₃ or be a raw material for producing Al ₂ O ₃ , in addition, it may contain one or more metal oxides other than Al ₂ O ₃ (including materials representing or containing an Al complex ₂ O ₃ and metal oxide (for example, Dy ₃ Al ₅ O ₁₂ , Y ₃ Al ₅ O ₁₂ , CeAl ₁₁ O ₁₈ , etc.)) or be the raw material for their preparation.

Sources, including those supplied to the market, of rare earth oxides include powdered rare earth metal oxides, rare earth metals, rare earth metal ores (e.g., bastnesite and monazite), rare earth metal salts, rare earth metal nitrates and rare earth carbonates. The source of rare earth metal oxide (s) may contain rare earth metal oxide (s) or it can only be a raw material for producing rare earth metal oxide (s). Alternatively, the source of rare earth metal oxide (s) may contain rare earth metal oxide (s) or be a raw material for producing rare earth metal oxide (s), in addition, it may contain one or more metal oxides other than rare earth metal oxide (s) (including materials representing or containing a complex of rare-earth metal oxide and other metal oxide (for example, Dy ₃ Al ₅ O ₁₂ , Y ₃ Al ₅ O ₁₂ , CeAl ₁₁ O ₁₈ , etc.)) or be a raw material for its (their) production .

Sources of Y ₂ O ₃ (based on theoretical studies of oxides), including marketed sources, include powdered yttrium, yttrium, yttrium-containing ores and yttrium salts (e.g., carbonates, nitrates, chlorides, yttrium hydroxides, and combinations thereof) . The source of Y ₂ O ₃ may contain Y ₂ O ₃ or it may be only a raw material for producing Y ₂ O ₃ . Alternatively, the source of Y ₂ O ₃ may contain Y ₂ O ₃ or be a raw material for the production of Y ₂ O ₃ , in addition, it may contain one or more metal oxides other than Y ₂ O ₃ (including materials representing or containing complex Y ₂ O ₃ and metal oxide (for example, Y ₃ Al ₅ O ₁₂ )) or be a raw material for their preparation.

Sources of ZrO ₂ (based on theoretical studies of oxides), including marketed sources, include powdered zirconium oxides, zirconium sand, zirconium, zirconium-containing ores and zirconium salts (e.g., carbonates, acetates, nitrates, chlorides, zirconium hydroxides, and their combinations). In addition, or alternatively, the source of ZrO ₂ may contain ZrO ₂ or it can only be a raw material for producing ZrO ₂ , and it can also contain oxides of other metals, such as hafnium or be a raw material for their production. Sources of HfO ₂ (based on theoretical studies of oxides), including marketed sources, include powdered hafnium oxides, hafnium, hafnium-containing ores and hafnium salts. In addition, or alternatively, the source of HfO ₂ may contain HfO ₂ or it may be only a raw material for producing HfO ₂ , and it may also contain oxides of other metals, such as ZrO ₂ , or be a raw material for their production.

Other metal oxides used may also include based on theoretical studies of oxides BaO, CaO, Cr ₂ O ₃ , CoO, Fe ₂ O ₃ , GeO ₂ , Li ₂ O, MgO, MnO, NiO, Na ₂ O, Sc ₂ O ₃ , SrO, TiO ₂ , ZnO and combinations thereof. Sources of oxides, including those supplied to the market, include pure oxides, oxide complexes, ores, carbonates, acetates, nitrates, chlorides, hydroxides and other oxide compounds. These metal oxides are added to change the physical properties of the resulting abrasive particles and / or to facilitate their processing. These metal oxides are typically added in an amount in the range from 0 to 50 wt.%, In some embodiments, implementation of the present invention preferably from 0 to 25 wt.%, And more preferably from 0 to 50 wt.% With respect to the mass of glass ceramics, depending on the property that it is desirable to obtain.

Specific sources of metal oxides and other additives used to produce ceramics in accordance with the present invention are typically selected depending on the given composition and microstructure of the final ceramic product, the given degree of crystallinity, if any, the required physical properties (e.g. hardness or impact strength) of the final ceramic product, the need to avoid the presence of unwanted impurities or minimize their amount, the specified properties of the final ceramic product and / or a specific method for producing ceramics (including equipment and any cleaning of raw materials before and / or during reflow and / or curing).

In some cases, it is preferable to include limited amounts of metal oxides selected from the group consisting of Na ₂ O, P ₂ O ₅ , SiO ₂ , TeO ₂ , V ₂ O _3, and combinations thereof. Sources of oxides, including those supplied to the market, include pure oxides, their complexes, ores, carbonates, acetates, nitrates, chlorides, hydroxides and other oxide compounds. These metal oxides can be added, for example, to change the physical properties of the resulting abrasive particles and / or to facilitate their processing. These metal oxides, when used, are typically added in an amount in the range of from more than 0 to 20 wt.%, Preferably from more than 0 to 5 wt.% And more preferably from more than 0 to 2 wt.% With respect to the mass glass ceramics depending on the property that you want to obtain.

In some embodiments of the present invention, it is preferred that at least a portion of the metal oxide source (in some embodiments of the present invention, preferably 10, 15, 20, 25, 30, 35, 40, 45, or even at least 50 wt.%) Is obtained adding to the melt a metal substance in the form of particles, which includes at least one of the metals (for example, Al, Ca, Cu, Cr, Fe, Li, Mg, Ni, Ag, Ti, Zr and their combinations) M, which have a negative enthalpy of oxide formation or, otherwise, metallize them using other raw materials rials. Although there is no theoretical basis, it is believed that the heat generated during the exothermic metal oxidation reaction favorably affects the formation of a homogeneous melt and the resulting amorphous material. For example, it is believed that the additional heat released in the oxidation reaction of the raw material compensates for the insufficient heat transfer and, therefore, facilitates the formation of the melt and increases its homogeneity, especially if amorphous particles are formed with dimensions x, y and z exceeding 150 micrometers. It is also believed that additional heat contributes to various chemical reactions and physical processes (for example, thickening and spheroidization) to completion. In addition, it is believed that in some embodiments of the present invention, the presence of additional heat released during the oxidation reaction actually facilitates the formation of a melt, which otherwise is inefficient or impractical due to the high melting point of the substances. In addition, the presence of additional heat released during the oxidation reaction actually facilitates the formation of amorphous material, otherwise the formation of amorphous material may not occur or it may not occur in the desired size range. Another advantage of the present invention is that in the formation of amorphous materials, many chemical and physical processes, such as melting, thickening, and spheroidization, can be completed within a short time interval and, therefore, very high quenching rates can be achieved. Additional detailed information can be found in the simultaneously pending US application with serial number 10/211639, filed simultaneously with this application.

The addition of certain metal oxides can alter the properties and / or crystal structure or microstructure of glass ceramics in accordance with the present invention, as well as the processing of raw materials and intermediates used in the preparation of glass ceramics. For example, observations have shown that the addition of oxides such as MgO, CaO, Li ₂ O and Na ₂ O leads to a change in both T _g (for glass) and T _x (where T _x is the crystallization temperature) of the amorphous material. Although there is no theoretical basis, it is believed that such additives affect the formation of glass. In addition, the addition of such oxides can, for example, reduce the melting temperature of the entire system (i.e., turn the system into a eutectic mixture with a lower melting point) and facilitate the formation of amorphous material. The presence of complex eutectic mixtures in multicomponent systems (quaternary, etc.) can increase the ability to form amorphous material. The addition of certain metal oxides, such as MgO, CaO, Li ₂ O and Na ₂ O, can also affect the viscosity of liquid melt and the viscosity of glass in the "working" range. The scope of the present invention also encompasses the inclusion of at least one of halogens (e.g., fluorine and chlorine) or chalcogenides (e.g., sulfides, selenides and tellurides) in amorphous materials and glass ceramics obtained from them.

The addition of certain substances may also affect the crystallization of amorphous material and ceramics containing amorphous material. For example, some metals, oxides (e.g. titanates and zirconates) and metal fluorides can act as nucleating agents, leading to improved heterogeneous nucleation of crystals. In addition, the addition of certain oxides can lead to a change in metastable phases, which lose their glassy nature when re-heating an amorphous material. In another embodiment, it is desirable to add metal oxides (for example, Y ₂ O ₃ , TiO ₂ , CaO and MgO) to ceramics containing crystalline ZrO ₂ , which are known to stabilize the tetragonal / cubic structure of ZrO ₂ .

Specific sources of metal oxides and other additives used to produce ceramics in accordance with the present invention are typically selected depending on the given composition and microstructure of the final ceramic product, the given degree of crystallinity, if any, the required physical properties (e.g. hardness or impact strength) of the final ceramic product, the need to avoid the presence of unwanted impurities or minimize their amount, the specified properties of the final ceramic product and / or a specific method for producing ceramics (including equipment and any cleaning of raw materials before and / or during reflow and / or curing).

Sources of metal oxides and other additives may be in any form suitable for the processing method and equipment used to produce glass ceramics in accordance with the present invention. Raw materials can be melted and quenched using methods and equipment known in the art that are used to produce amorphous oxide materials and amorphous metals. Desired cooling rates are 50 K / s and higher. Known cooling methods in the art include roller cooling. Roller cooling can be carried out, for example, as follows: sources of metal oxides are melted at a temperature that is usually higher than the melting point by 20-200 ° C, and the melt is cooled / quenched by spraying it at high pressure (for example, using a gas such as air, argon, nitrogen, etc.) onto the roller (s) rotating (rotating) at a high speed. Typically, the rollers are made of metal and cooled with water. For cooling / quenching of the melt, metal molds with a vertical book-type connector can also be used.

Other methods for producing melts, cooling / quenching of melts, and / or otherwise producing amorphous material include vapor quenching, melt discharge, plasma spraying, and gas or centrifugal spraying. Vapor quenching is carried out, for example, by spraying, where the used metal melts or sources of metal oxides are formed into the target (s) of the ion spraying apparatus. The target is fixed in a predetermined position in the spraying device, and the substrate (s) to be coated are placed opposite the target (s). Typically, the pressure of gaseous oxygen and gaseous Ar is 10 ⁻³ torr, a discharge forms between the target (s) and the substrate (s), and Ar or oxygen ions collide with the target, initiating a sputtering reaction, which leads to the deposition of the film on the substrate . Other details regarding plasma spraying can be found, for example, in the simultaneously pending U.S. application serial number 10/211640, filed simultaneously with this application.

Gas spraying involves the melting of the starting particles with their transformation into a melt. A thin stream of such a melt is sprayed as a result of contact with a discontinuous stream of air (i.e., the stream is divided into small droplets). Subsequently, substantially discrete, typically ellipsoidal particles (e.g., droplets) including amorphous material are recovered. Examples of particle sizes include a diameter in the range of from about 5 micrometers to about 3 mm. The release of the melt can be carried out, for example, by the method described in US patent No. 5605870 (Strom-Olsen and others). To obtain substances in accordance with the present invention, it is also possible to use a containerless technology for producing glass using laser beam heating, as described, for example, in PCT application publication no. WO 01/27046 A1, published April 4, 2001.

It is believed that the cooling rate affects the properties of the quenched amorphous material. For example, the glass transition temperature, density, and other properties of glass typically vary with cooling rate.

As a rule, it is preferable if the base material contains at least 50, 60, 75, 80, 85, 90, 95, 98, 99, or even 100 wt.% Of amorphous material.

Rapid cooling can also be carried out in a controlled atmosphere, for example, in a reducing, neutral or oxidizing environment, to maintain and / or change the specified oxidation states, etc. in the process of cooling. The atmosphere can also influence the formation of amorphous material by changing the kinetics of crystallization from a supercooled liquid. For example, it was published that in an argon atmosphere it is possible to achieve stronger supercooling of an Al ₂ O ₃ melt without crystallization than in an air atmosphere.

The microstructure of the phase composition (glassy / amorphous / crystalline) of the material can be determined in various ways. For example, using optical microscopy, electron microscopy, differential thermal analysis (DTA) and X-ray diffraction (RD), you can get a variety of information.

For optical microscopy, an amorphous material is generally predominantly transparent due to the absence of such light scattering centers as the crystal interface, while crystalline material is opaque due to light scattering effects due to the crystal structure.

The percentage yield of balls of amorphous material is calculated using a fraction with a size of -100 + 120 mesh (i.e., a fraction collected using a sieve with openings ranging in size from 150 micrometers to 125 micrometers). The calculations are as follows. The balls are distributed on a glass slide so that one layer is obtained, and they are examined under an optical microscope. Using the crosshair of the eyepiece of an optical microscope as a guide, consider amorphous or crystalline, depending on the optical transparency, balls located along a straight line. A total of 500 balls are counted and the percentage yield of balls of amorphous material is determined by dividing the number of amorphous balls by the total number of balls.

According to the results of DTA, a substance is classified as amorphous if the corresponding DTA curve reflects an exothermic crystallization event (T _x ). If such a curve reflects an endothermic event (T _g ) at a temperature below T _x , then it is believed that the substance consists of a glass phase. If the DTA curve does not reflect such events, consider that the substance contains crystalline phases.

Differential thermal analysis (DTA) can be carried out as follows. For DTA (conducted on an instrument such as obtained from Netzsch Instruments, Selb, Germany, under the trade name "NETZSCH STA 409 DTA / TGA"), a fraction with a size of -140 + 170 mesh (i.e. a fraction collected using a sieve) is used with openings ranging in size from 105 micrometers to 90 micrometers). A specific amount of each sample to be analyzed (usually approximately 400 milligrams (mg)) is placed in a 100 microliter sample holder of Al ₂ O ₃ . Each sample is heated in still air at a rate of 10 ° C / min from room temperature (approximately 25 ° C) to 1100 ° C.

Using X-ray powder diffractometry (XRD) (carried out on an X-ray diffractometer, for example, "PHILLIPS XRG 3100" from Phillips, Machwah, NJ, when copper emits radiation K α1 with a wavelength of 1.54050 Angstroms) phases present in substance, can be identified by comparing the peaks on the XRD curve obtained for the crystallized material, with databases published by the International Center for Diffraction Data, according to XRD diagrams obtained for crystalline phases provided by the Joint Committee Powder Diffraction Standards (JCPDS - Joint Committee on Powder Diffraction Standards). In addition, XRD can be used to qualitatively determine phase types. The presence of a wide smeared intensity peak indicates the amorphous nature of the material. The presence of both a broad peak and pronounced peaks indicates the presence of crystalline material in an amorphous basis.

The size of the initially formed amorphous material or ceramic (including glass before crystallization) may be larger than the specified size. Amorphous material or ceramics can be converted into smaller particles using crushing and / or grinding methods known in the art, including crushing on a roller mill, core grinding, crushing on a jaw crusher, hammer grinding, ball grinding, jet grinding, impact grinding etc. In some cases, it is desirable for the crushing stages to be two or more. For example, particles of the obtained (cured) ceramics may be larger than specified. The first stage of crushing may include grinding these relatively large masses or "pieces" to produce smaller particles. These pieces can be milled using a hammer mill, impact mill or jaw mill. The resulting smaller particles can be subsequently crushed to obtain particles with a given size distribution. Sometimes, to obtain particles with a given size distribution (also called grain size or grade), several stages of crushing are necessary. As a rule, the crushing conditions are optimized so as to obtain particles with a given (given) shape (s) and with a given size distribution. The resulting particles that do not fit the specified size can be re-crushed if they are too large or they can be reused as raw material for remelting if they are too small.

The shape of the ceramic (including glass before crystallization) may depend, for example, on the composition and / or microstructure of the ceramic, the configuration of the container in which it is cooled, and the crushing method (i.e., the crushing method used). Generally, if a “blocky” form is preferred, more energy is used to produce it. Conversely, if a “pointed” shape is preferred, more energy is used to produce it. To obtain different specified forms, you can also use different methods of crushing. The average ratio of profile height to width can range from 1: 1 to 5: 1, usually from 1.25: 1 to 3: 1, and preferably from 1.5: 1 to 2.5: 1.

It is also within the scope of the present invention to directly produce ceramics (including glass before crystallization) of a given shape. For example, ceramics (including glass before crystallization) can be obtained (including molding) by pouring or casting the melt into a mold.

The scope of the present invention also includes the manufacture of ceramics (including glass before crystallization) by the coalescence method. In the process of the coalescence step, a larger body is formed from essentially two or more small particles. For example, an amorphous material, including particles (obtained, for example, by crushing) (including balls and microspheres), fibers, etc., can be formed into particles of a larger size. For example, ceramics (including glass before crystallization) can also be obtained by heating, for example, particles, including amorphous material, and / or fibers, etc., to a temperature exceeding T _g , as a result of which the particles and others coalesce to form, and by cooling the resulting form. The temperature and pressure used for coalescence may depend, for example, on the composition of the amorphous material and the desired density of the final product. The temperature should be below the crystallization temperature of the glass, and for glass, above the glass transition temperature. In some embodiments, implementation of the present invention, the heating is carried out at least one temperature in the range from about 850 ° C to 1100 ° C (in some embodiments, implementation of the present invention is preferably from 900 ° C to 1000 ° C). As a rule, to facilitate the coalescence of an amorphous material, it is carried out under pressure (for example, from a value exceeding zero to 1 GPa or higher). In one embodiment of the present invention, a batch of particles, etc., is placed in a mold and hot pressed at a temperature higher than the glass transition temperature, resulting in a viscous glass stream leading to coalescence to produce a relatively large body. Examples of traditional coalescence methods include hot pressing, hot isostatic pressing, hot extrusion pressing, etc. As a rule, it is preferable to cool the body obtained as a result of coalescence before further heat treatment. After heat treatment, if necessary, the body obtained as a result of coalescence can be crushed into smaller particles or particles with a given size distribution.

The scope of the present invention also includes additional heat treatment to further improve the required properties of the material. For example, to eliminate residual porosity and increase the density of the material, hot isostatic pressing can be used (for example, at a temperature of about 900 to 1400 ° C.). Optionally, the product obtained as a result of coalescence can be subjected to heat treatment to obtain glass ceramics, crystalline ceramics or ceramics that otherwise include crystalline ceramics.

The coalescence of amorphous material and / or glass ceramics (e.g. particles) can be carried out using a number of methods, including sintering at elevated or normal pressure (e.g., sintering, plasma sintering, hot pressing, hot isostatic pressing), hot forging, hot extrusion pressing, etc.).

Heat treatment can be carried out in various ways, including methods known in the art for heat treating glass to produce glass ceramics. For example, the material can be cooked in batches using resistive, induction or gas furnaces. Alternatively, it is possible to carry out, for example, heat treatment of a continuous flow of material using rotary kilns. In the case of using a rotary kiln, the material is fed directly to the furnace in which the elevated temperature is set. The exposure time of the elevated temperature can vary from a few seconds (in some embodiments, even less than 5 seconds) and several minutes to several hours. The temperature may range from about 900 to 1600 ° C, usually from 1200 to 1500 ° C. It is also within the scope of the present invention to conduct heat treatment of the material using a batch process (for example, to ensure crystal nucleation) or a continuous process (for example, to ensure crystal growth and to achieve a given density). At the stage of crystal nucleation, the temperature usually varies from about 900 to 1100 ° C., In some embodiments, implementation of the present invention from about 925 to 1050 ° C. Similarly, in the step of achieving a predetermined density, the temperature usually varies from about 1100 to 1600 ° C., in some embodiments, preferably from 1200 to 1500 ° C. This heat treatment can be carried out, for example, feeding the material directly into the furnace at elevated temperature. Alternatively, for example, the material can be fed into the oven at a much lower temperature (for example, at room temperature) and then heated to a predetermined temperature at a predetermined speed. It is also within the scope of the present invention to conduct heat treatment in an atmosphere other than air. In some cases, it may even be desirable to conduct heat treatment in a reducing atmosphere (s). In addition, for example, it may be desirable to carry out heat treatment under gas pressure, as in the case of a hot-pressing hydrostat or in the case of a gas furnace under pressure. It is also within the scope of the present invention to convert (for example, by crushing) the resulting product or heat-treated product into particles (e.g., abrasive particles).

The amorphous material is subjected to heat treatment in order to cause at least partial crystallization with the formation of glass ceramics. The heat treatment of some glasses leading to the formation of glass ceramics is well known in the art. For a number of glasses, heating conditions are known, leading to the nucleation of crystals and the formation of glass ceramics. Alternatively, one of skill in the art can determine the appropriate conditions from an analysis of the isothermal conversion (TTT) of the glass using methods known in the art. A person skilled in the art, after reading the description of the present invention, will be able to construct TTT curves for glasses prepared in accordance with the present invention and determine suitable conditions for nucleation and / or growth of crystals to form ceramics in accordance with the present invention.

As a rule, glass ceramics are stronger than the amorphous material from which it is obtained. Therefore, the strength of the material can be adjusted, for example, by changing the degree of conversion of the amorphous material into crystalline (s) ceramic (s) phase (s). Alternatively or in addition to the above, the strength of the material can be influenced, for example, by the number of crystallization centers, which can also affect the number and size of crystals of the crystalline (s) phase (s). Further details regarding the manufacture of glass ceramics can be found, for example, in Glass-Ceramics, P.W. McMillan, Academic Press, Inc., 2nd edition, 1979.

For example, during the heat treatment of typical amorphous materials, leading to the formation of glass ceramics according to the present invention, the formation of phases such as La ₂ Zr ₂ O ₇ and, in the presence of ZrO ₂ , cubic / tetragonal ZrO ₂ , in some cases monoclinic ZrO ₂ observed at a temperature exceeding approximately 900 ° C. Although there is no theoretical basis, it is believed that phases containing zirconium are the first to crystallize from an amorphous material. Presumably, the formation of phases Al ₂ O ₃ , ReAlO ₃ (where Re denotes a cation of at least one rare-earth metal), ReAl ₁₁ O ₁₈ , Re ₃ Al ₅ O ₁₂ , Y ₃ Al ₅ O ₁₂ , etc., usually occurs when temperatures exceeding approximately 925 ° C. As a rule, the order of the size of the crystals during the nucleation stage is measured by nanometers. For example, the formation of crystals with a size of 10-15 nanometers was observed. In at least some embodiments, implementation of the present invention, heat treatment at approximately 1300 ° C for approximately 1 hour provides complete crystallization. Typically, the heat treatment time for each of the stages of crystal nucleation and growth can vary from a few seconds (in some embodiments even less than 5 seconds) and several minutes to an hour or more.

The size of the obtained crystals, as a rule, can be adjusted, at least in part, by changing the time and / or temperature of nucleation and / or crystallization. Although it is generally preferable to have small crystals (for example, the order of size of which does not exceed a micrometer or even a nanometer), glass ceramics in accordance with the present invention containing crystals of larger sizes (for example, at least 1-10 micrometers, not less than 10-25 micrometers, not less than 50-100 micrometers or even more than 100 micrometers). Although there is no theoretical basis, it is generally accepted in this area that the smaller the size of the crystals (at the same density), the better the mechanical properties (for example, hardness and strength) of the ceramic.

Examples of crystalline phases which may be present in embodiments of glass-ceramics according to an embodiment of the present invention include Al ₂ O ₃ (e.g., α-Al ₂ O _3), Y ₂ O _3, REO, HfO _2, ZrO ₂ (e.g., cubic ZrO ₂ and tetragonal ZrO ₂ ), BaO, CaO, Cr ₂ O ₃ , CoO, Fe ₂ O ₃ , GeO ₂ , Li ₂ O, MgO, MnO, NiO, Na ₂ O, P ₂ O ₅ , Sc ₂ O ₃ , SiO ₂ , SrO, TeO ₂ , TiO ₂ , V ₂ O ₃ , Y ₂ O ₃ , ZnO, "complex metal oxides" (including the "Al ₂ O ₃ metal oxide complex (e.g., the Al ₂ O ₃ -REO complex (e.g. ReAlO ₃ (e.g. GdAlO ₃ , LaAlO ₃ ), ReAl ₁₁ O ₁₈ (e.g. LaAl ₁₁ O ₁₈ ) and Re ₃ Al ₅ O ₁₂ (e.g. Dy ₃ Al ₅ O ₁₂ )), Al ₂ O ₃ -Y complex ₂ O ₃ (e.g. Y ₃ Al ₅ O ₁₂ ) and the ZrO ₂ —REO complex (for example, Re ₂ Zr ₂ O ₇ (for example, La ₂ Zr ₂ O ₇ ))) and combinations thereof.

It is also within the scope of the present invention to replace part of the yttrium and / or aluminum cations in the Al ₂ O ₃ metal oxide complex (for example, the Al ₂ O ₃ -Y ₂ O ₃ complex (for example, yttrium aluminate having a garnet crystal structure)) with other cations . For example, part of the Al cations in the Al ₂ O ₃ —Y ₂ O ₃ complex can be replaced by at least one cation of an element selected from the group consisting of Cr, Ti, Sc, Fe, Mg, Ca, Si, Co, and combinations thereof . For example, part of the Y cations in the Al ₂ O ₃ —Y ₂ O ₃ complex can be replaced by at least one cation of an element selected from the group consisting of Ce, Dy, Er, Eu, Gd, Ho, La, Lu, Nd, Pr, Sm, Th, Tm, Yb, Fe, Ti, Mn, V, Cr, Co, Ni, Cu, Mg, Ca, Sr, and combinations thereof. Similarly, it is also within the scope of the present invention to replace a portion of the aluminum cations in alumina. For example, aluminum in alumina can be replaced with Cr, Ti, Sc, Fe, Mg, Ca, Si, and Co. As described above, the replacement of cations can affect the properties (for example, hardness, toughness, strength, thermal conductivity, etc.) of the fused material.

It is also within the scope of the present invention to replace part of the cations of rare earth metal and / or aluminum in the Al ₂ O ₃ metal oxide complex (for example, the Al ₂ O ₃ -REO complex) with other cations. For example, part of the Al cations in the Al ₂ O ₃ -REO complex can be replaced by at least one cation of an element selected from the group consisting of Cr, Ti, Sc, Fe, Mg, Ca, Si, Co, and combinations thereof. For example, part of the Y cations in the Al ₂ O ₃ -REO complex can be replaced by at least one cation of an element selected from the group consisting of Y, Fe, Ti, Mn, V, Cr, Co, Ni, Cu, Mg, Ca , Sr, and combinations thereof. Similarly, it is also within the scope of the present invention to replace a portion of the aluminum cations in alumina. For example, aluminum in alumina can be replaced with Cr, Ti, Sc, Fe, Mg, Ca, Si, and Co. As described above, the replacement of cations can affect the properties (for example, hardness, toughness, strength, thermal conductivity, etc.) of the fused material.

The average crystal size can be determined using the method of intersecting lines in accordance with ASTM E 112-96 "Standard analytical methods for determining the average grain size". The sample is set in a base resin (for example, resin with the trade name "TRANSOPTIC POWDER" from Buehler, Lake Bluff, Illinois), which is typically in the form of a cylinder with a diameter of approximately 2.5 cm and a height of approximately 1.9 cm An established fragment is prepared using conventional polishing methods using a polishing tool (similar to that obtained from Buehler, Lake Bluff, Ill., Under the trade name "ECOMET 3"). The sample is polished for 3 minutes with a diamond grinding wheel and then polished for 5 minutes with each of the suspensions containing particles of sizes 45, 30, 15, 9, 3 and 1 micrometer. A fixed and polished sample is metallized with a thin layer of a gold alloy with palladium and observed using a scanning electron microscope (such as JEOL SEM, model JSM 840A). The average crystal size is determined using a conventional micrograph of a microstructure of a sample obtained using a back-scattered electron micrograph (BSE), as follows. Count the number of crystals per unit length (N _L ) of an arbitrary straight line drawn through a micrograph. The average crystal size is determined on the basis of this number according to the equation below.

where N _L denotes the number of crystals per unit length, and M denotes an increase in micrograph.

Some embodiments of the present invention include glass ceramics containing alpha alumina in which at least one average crystal size does not exceed 150 nanometers.

Some embodiments of the present invention include glass ceramics containing alpha alumina, where at least 90 (in some embodiments of the present invention, preferably 95 or even 100) percent of the amount of alpha alumina present in such a portion is in the form of crystals whose sizes do not exceed 200 nanometers.

Some embodiments of the present invention include glass ceramics comprising alpha Al ₂ O ₃ , crystalline ZrO ₂ and a first Al ₂ O ₃ —Y ₂ O ₃ complex, wherein at least one of alpha Al ₂ O ₃ , crystalline ZrO _2, or a first Al complex ₂ O ₃ -Y ₂ O ₃ is in the form of crystals, the average size of which does not exceed 150 nanometers. In some embodiments, implementation of the present invention, it is preferable that the glass ceramic further includes a second, different from the first, complex Al ₂ O ₃ -Y ₂ O ₃ . In some embodiments of the present invention, it is preferred that the glass ceramic further comprises an Al ₂ O ₃ -REO complex.

Some embodiments of the present invention include glass ceramics containing the first Al ₂ O ₃ -Y ₂ O ₃ complex, a second, different from the first, Al ₂ O ₃ -Y ₂ O ₃ complex, and crystalline ZrO ₂ , where at least one of the first complex Al ₂ O ₃ -Y ₂ O ₃ , the second complex of Al ₂ O ₃ -Y ₂ O ₃ or crystalline ZrO ₂ at least 90 (in some embodiments, preferably 95 or even 100 percent) consists of crystals, sizes which do not exceed 200 nanometers. In some embodiments, implementation of the present invention, it is preferable that the glass ceramic further includes a second, different from the first, complex Al ₂ O ₃ -Y ₂ O ₃ . In some embodiments of the present invention, it is preferred that the glass ceramic further comprises an Al ₂ O ₃ -REO complex.

Some embodiments of the present invention include glass ceramics comprising alpha Al ₂ O ₃ , crystalline ZrO _2, and a first Al ₂ O ₃ -REO complex, wherein at least one of alpha Al ₂ O ₃ , crystalline ZrO _2, or a first Al ₂ O ₃ complex -REO, crystals of which on average in size do not exceed 150 nanometers. In some embodiments, implementation of the present invention, it is preferable that the glass ceramic further includes a second, different from the first, complex Al ₂ O ₃ -REO. In some embodiments of the present invention, it is preferable that the glass ceramics further comprise an Al ₂ O ₃ —Y ₂ O ₃ complex.

Some embodiments of the present invention include glass ceramics containing a first Al ₂ O ₃ -REO complex, a second, different from the first, Al ₂ O ₃ -REO complex and crystalline ZrO ₂ , where at least one of the first Al ₂ O ₃ -REO complex , the second complex of Al ₂ O ₃ -REO or crystalline ZrO ₂ at least 90 (in some embodiments, preferably 95 or even 100) percent consists of crystals whose sizes do not exceed 200 nanometers. In some embodiments of the present invention, it is preferable that the glass ceramics further comprise an Al ₂ O ₃ —Y ₂ O ₃ complex.

Some embodiments of the present invention include glass ceramics comprising a first Al ₂ O ₃ -Y ₂ O ₃ complex, a second, different from the first, Al ₂ O ₃ -Y ₂ O ₃ complex, and crystalline ZrO ₂ , where at least one of the first complex Al ₂ O ₃ -Y ₂ O ₃ , the second, different from the first, complex Al ₂ O ₃ -Y ₂ O ₃ or crystalline ZrO ₂ , the average crystal size of which does not exceed 150 nanometers. In some embodiments, implementation of the present invention, it is preferable that the glass ceramic further includes a second, different from the first, complex Al ₂ O ₃ -Y ₂ O ₃ . In some embodiments of the present invention, it is preferred that the glass ceramic further comprises an Al ₂ O ₃ -REO complex.

Some embodiments of the present invention include glass ceramics comprising a first Al ₂ O ₃ -Y ₂ O ₃ complex, a second, different from the first, Al ₂ O ₃ -Y ₂ O ₃ complex, and crystalline ZrO ₂ , where at least one of the first complex Al ₂ O ₃ -Y ₂ O ₃ , a second, different from the first, complex Al ₂ O ₃ -Y ₂ O ₃ or crystalline ZrO ₂ by at least 90 (in some embodiments of the present invention, preferably 95 or even 100) percent consists of crystals whose sizes do not exceed 200 nanometers. In some embodiments of the present invention, it is preferred that the glass ceramic further comprises an Al ₂ O ₃ -REO complex.

Some embodiments of the present invention include glass ceramics containing a first Al ₂ O ₃ -REO complex, a second, different from the first, Al ₂ O ₃ -REO complex and crystalline ZrO ₂ , where at least one of the first Al ₂ O ₃ -REO complex , the second, different from the first, complex Al ₂ O ₃ -REO or crystalline ZrO ₂ is in the form of crystals, the average size of which does not exceed 150 nanometers. In some embodiments, implementation of the present invention, it is preferable that the glass ceramic further comprises a second, different from the first, complex Al ₂ O ₃ -REO. In some embodiments of the present invention, it is preferable that the glass ceramics further comprise an Al ₂ O ₃ —Y ₂ O ₃ complex.

Some embodiments of the present invention include glass ceramics containing a first Al ₂ O ₃ -REO complex, a second, different from the first, Al ₂ O ₃ -REO complex and crystalline ZrO ₂ , where at least one of the first Al ₂ O ₃ -REO complex , the second, different from the first, complex Al ₂ O ₃ -REO or crystalline ZrO ₂ at least 90 (in some embodiments of the present invention preferably 95 or even 100) percent consists of crystals whose sizes do not exceed 200 nanometers. In some embodiments of the present invention, it is preferable that the glass ceramics further comprise an Al ₂ O ₃ —Y ₂ O ₃ complex.

In some embodiments, implementation of the present invention, the glass ceramics in accordance with the present invention at least 75, 80, 85, 90, 95, 97, 98, 99, or even 100 percent by volume consists of crystals, where the average crystal size is less than 1 micrometer. In some embodiments, implementation of the present invention, the crystal content in the glass ceramics in accordance with the present invention is not more than at least 75, 80, 85, 90, 95, 97, 98, 99, or even 100 volume percent, where the average crystal size does not exceed 0 5 micrometers. In some embodiments, implementation of the present invention, the crystal content in the glass ceramics in accordance with the present invention is less than 75, 80, 85, 90, 95, 97, 98, 99, or even 100 volume percent, where the average crystal size does not exceed 0.3 micrometers. In some embodiments, implementation of the present invention, the crystal content in the glass ceramics in accordance with the present invention is less than at least 75, 80, 85, 90, 95, 97, 98, 99, or even 100 volume percent, where the average crystal size does not exceed 0, 15 micrometers.

The crystals obtained by heat treatment of an amorphous material, leading to the formation of glass ceramics variants in accordance with the present invention, can have an equiaxed, columnar or flattened flat configuration.

Although glass ceramics in accordance with the present invention can be used as a base material, it is within the scope of the present invention to provide composites comprising glass ceramics in accordance with the present invention. Such a composite may contain, for example, a phase or fibers (solid or non-continuous) or particles (including filamentary) (for example, metal oxide particles, boride particles, carbide particles, nitride particles, diamond particles, metal particles, glass particles, and combinations thereof) dispersed in glass ceramics in accordance with the present invention, or it may have a multilayer structure (representing, for example, a gradual transition from glass ceramics in accordance with the present invention to an amorphous material, and uses to obtain the glass-ceramic and / or glass-ceramic fibers that are the subject of the present invention prepared from various mixtures).

Typically, the (true) density, sometimes called specific gravity, of a ceramic in accordance with the present invention is at least 70% of the theoretical density. More preferably, the (true) density of the ceramic in accordance with the present invention is at least 75%, 80%, 85%, 90%, 92%, 95%, 96%, 97%, 98%, 99%, 99.5% or even 100% of theoretical density. Abrasive particles in accordance with the present invention have a density of at least 85%, 90%, 92%, 95%, 96%, 97%, 98%, 99%, 99.5%, or even 100% of theoretical density.

The average hardness of the material of the present invention can be determined as follows. Fragments of the sample are set in the base resin (for example, resin with the trade name "TRANSOPTIC POWDER" from Buehler, Lake Bluff, Illinois), which is usually in the form of a cylinder with a diameter of approximately 2.5 cm and a height of approximately 1.9 see. An established fragment is prepared using traditional polishing methods using a polishing tool (similar to that supplied by Buehler, Lake Bluff, Ill., under the trade name "ECOMET 3"). The sample is polished for approximately 3 minutes with a diamond grinding wheel and then polished for 5 minutes with each of the suspensions containing particles of sizes 45, 30, 15, 9, 3 and 1 micrometer. Microhardness is measured using a conventional microhardness tester (similar to that supplied by Mitutoyo Corporation, Tokyo, Japan, under the trade name "MITUTOYO MVK-VL") equipped with a Vickers indenter with an indentation force of 100 grams. Microhardness is measured in accordance with the recommendations of ASTM Test Method E384 Test Methods for Microhardness of Materials (1991).

The average hardness of the abrasive particles in accordance with the present invention is at least 15 GPa, in some embodiments, the implementation of the present invention is at least 16 GPa, at least 17 GPa, or even at least 18 GPa.

Other details regarding amorphous materials and glass ceramics, including their preparation, use and properties, can be found in US applications having serial numbers 09/922526, 09/922527 and 09/922530, filed August 2, 2001, and serial numbers 10/211598, 10/211630, 10/211639, 10/211034, 10/211044, 10/211628, 10/211640 and 10/211684, filed simultaneously with this application.

Abrasive particles in accordance with the present invention typically include crystalline ceramics (in some embodiments, the implementation of the present invention preferably at least 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99 , 99.5 or even 100 volume percent) of crystalline ceramics.

The abrasive particles in accordance with the present invention can be passed through a sieve and sorted using methods well known in the art using industry-recognized classification standards such as ANSI (American National Standards Institute), FEPA (European Abrasive Manufacturers Federation) standards and JIS (Japanese Industry Standards). The sizes of abrasive particles in accordance with the present invention can be in a wide range, typically varying from about 0.1 to 5000 micrometers, more often from about 1 to 2000 micrometers; preferably from about 5 to 1500 micrometers, more preferably from about 100 to 1500 micrometers.

ANSI classification categories include: ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI 24, ANSI 36, ANSI 40, ANSI 50, ANSI 60, ANSI 80, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI 240, ANSI 280, ANSI 320, ANSI 360, ANSI 400 and ANSI 600. Preferred ANSI discharges for abrasive particles in accordance with the present invention are ANSI 8-220. FEPA classification discharges include P8, P12, P16, P24, P36, P40, P50, P60, P80, P100, P120, P150, P180, P220, P320, P400, P500, P600, P800, P1000 and P1200. Preferred FEPA discharges for abrasive particles in accordance with the present invention are P12-P220. JIS classification bits include JIS8, JIS12, JIS16, JIS24, JIS36, JIS46, JIS54, JIS60, JIS80, JIS100, JIS150, JIS180, JIS220, JIS240, JIS280, JIS320, JIS360, JIS400, JIS6001, JIS00, JIS001, JIS00, JIS800, JIS00, JIS00, JIS800, JIS00 JIS4000, JIS6000, JIS8000 and JIS10000. Preferred JIS discharges for abrasive particles in accordance with the present invention are JIS8-220.

After crushing and sorting, as a rule, abrasive particles are obtained having a different size distribution or belonging to different discharges. The resulting sets of discharges may not correspond to the needs of the manufacturer or supplier at this particular time. In order to reduce inventory to a minimum, non-demanding fractions can be reused in the melt to produce amorphous material. Reuse is carried out after the crushing stage, where the particles are present in the form of large lumps or smaller pieces (sometimes called "small"), which do not have a specific size distribution.

In another aspect, the present invention provides a method for producing abrasive particles, which comprises heat treating an amorphous material (eg, glass) containing particles, as a result of which at least a portion of the amorphous material is converted to glass ceramics to produce abrasive particles containing glass ceramic. In another embodiment, the present invention provides a method for producing abrasive particles containing glass ceramics, which includes heat treatment of an amorphous material, as a result of which at least a portion of the amorphous material is converted to glass ceramics, and crushing the material obtained after heat treatment to produce abrasive particles. When glass is crushed, sharper particles are obtained than when crushed substantially crystallized glass ceramics or crystalline material.

In another aspect, the present invention provides agglomerate abrasive grains, each of which contains a combination of abrasive particles in accordance with the present invention, held together by a binder. In another aspect, the present invention provides an abrasive product (e.g., coated abrasive products, bonded abrasive products (including glass, grinding and metal bonding grinding wheels, cutting wheels, grinding heads and honing blocks), non-woven abrasive products and abrasive brushes ), comprising a binder and a combination of abrasive particles, which (including agglomerated abrasive particles) are at least partially particles in accordance with this a complete invention. Methods for the preparation and use of such abrasive products are known to those skilled in the art. In addition, the abrasive particles in accordance with the present invention can be used in grinding methods using abrasive particles, for example, using suspensions of grinding compounds (e.g. polishing compounds), grinding, shot blasting, vibratory mill, etc.

Coated abrasive products typically include a base, abrasive particles, and at least one binder holding the abrasive particles on the base. The basis can be any suitable material, including fabric, polymer film, pulp, non-woven materials, paper, their combinations and modified options. As a binder, any binder can be used, including an inorganic or organic binder (including thermally cured resins and radiation cured resins). Abrasive particles may be present in a single layer or in two layers of a coated abrasive article.

An example of a coated abrasive article in accordance with the present invention is shown in FIG. In accordance with this drawing, an abrasive article in accordance with the present invention with a coating 1 consists of a base (substrate) 2 and an abrasive layer 3. The abrasive layer 3 includes abrasive particles 4 in accordance with the present invention, held on the main surface of the substrate 2 by the forming coating 5 and adhesive coating 6. In some cases, an ultra-adhesive coating (not shown) is used.

Binder abrasive products typically include a molded mass of abrasive particles held together by an organic, metal, or glass-like binder. A product formed from this mass may be, for example, a wheel, such as a grinding wheel or a cutting wheel. The diameter of the grinding wheels typically varies from about 1 cm to more than 1 meter, the diameter of the cutting wheels varies from about 1 cm to more than 80 cm (more preferably from about 3 cm to 50 cm). The thickness of the cutting wheel usually varies from about 0.5 mm to 5 cm, more often from about 0.5 mm to 2 cm. The molded mass can also be in the form, for example, of a honing bar, segment, grinding head, wheel (for example, radially double-circle sander) or another traditionally bonded shape. Binder abrasive products typically include about 3-50 vol.% Binder, about 30-90 vol.% Abrasive particles (or mixtures of abrasive particles), up to 50 vol.% Additives (including grinding enhancers), up to 70 vol.% Pores relative to the total volume of the abrasive product with a binder.

The preferred form is a grinding wheel. Figure 2 shows the grinding wheel 10 in accordance with the present invention, which includes abrasive particles 11 in accordance with the present invention, molded into a circle and mounted on the sleeve 12.

Non-woven abrasive products typically include an open porous, high polymeric fibrous structure, where the abrasive particles in accordance with the present invention are distributed throughout the structure and are held therein by an organic binder. Examples of fibers include polyester fibers, polyamide fibers and polyaramide fibers. Figure 3 schematically shows with a magnification of 100x a typical abrasive product in accordance with the present invention on a non-woven basis. Such an abrasive product in accordance with the present invention on a nonwoven basis includes, as a basis, a fibrous substrate 50 on which the abrasive particles 52 in accordance with the present invention are held by a binder 54.

Used abrasive brushes include brushes having a set of bristles that are common with the base (see, for example, US patent No. 5427595 (Pihl and others), 5443906 (Pihl and others), 5679067 (Johnson and others) and 5903951 (Ionta and etc.)). Preferably, such brushes are obtained by injection molding a mixture of polymer and abrasive particles.

Organic binders suitable for making abrasive products include thermosetting organic polymers. Examples of suitable thermosetting organic polymers include phenolic resins, urea-formaldehyde resins, melamine-formaldehyde resins, urethane resins, acrylate resins, polyester resins, amino plastics having side chains with α, β-unsaturated carbonyl groups, epoxies, urethane acrylic resins, alkyd acrylic resins and alkyd acrylic resins. The binder and / or abrasive product may include additives such as fibers, lubricants, moisturizers, thixotropic materials, surfactants, pigments, dyes, antistatic agents (e.g. carbon black, vanadium oxide, graphite, etc.), binders (e.g. silanes, titanates, zircoaluminates, etc.), plasticizers, suspending agents, etc. The amount of these optional additives is selected to provide the desired properties. Binders can improve adhesion to abrasive particles and / or filler. A binder from a chemical point of view can be thermoset, radiation curable, or a combination thereof. Other details regarding the chemical properties of binders can be found in US Pat. Nos. 4,588,419 (Caul et al.), 4,751,138 (Tumey et al.) And 5,436,063 (Follett et al.).

With regard to glassy binder abrasives, glassy binder materials having an amorphous structure and usually in a solid state are well known in the art. In some cases, the vitreous binder comprises crystalline phases. The glassy binder abrasive articles of the present invention may be in the form of a circle (including cutting wheels), a honing block, a grinding head, or other conventional binder shape abrasive. A preferred abrasive product in accordance with the present invention with a vitreous binder is a grinding wheel.

Examples of metal oxides used to produce glassy binders include silica, silicates, alumina, soda, calcium oxide, potassium oxide, titanium oxide, iron oxide, zinc oxide, lithium oxide, magnesium oxide, boron oxide, aluminum silicate, borosilicate glass, lithium aluminum silicate, their combinations, etc. As a rule, mixtures containing from 10% to 100% glassy frit can be used to produce glassy binders, although mixtures containing 20% to 80% glassy frit or 30% to 70% glassy frit are more often used. The rest of the glassy binder is non-frit material. Alternatively, a frit-free mixture may be used to produce a vitreous binder. Typically, glassy binders are held at a temperature in the range of about 700 to 1500 ° C., usually in the range of about 800 to 1300 ° C., sometimes in the range of about 900 to 1200 ° C., or even in the range of about 950 to 1100 ° FROM. The true temperature at which the binder matures depends, for example, on the chemical composition of a particular binder.

Preferred vitreous binders may include materials containing silica, alumina (preferably at least 10 wt.% Alumina) and boron oxide (preferably at least 10 wt.% Boron). In most cases, the glassy binder material further comprises an alkali metal oxide (s) (s) (e.g., Na ₂ O and K ₂ O) (in some cases, at least 10% by weight of alkali oxide (s) metal (s)).

Binder materials may also contain fillers or grinding enhancers, typically in the form of a granular material. Granular materials are typically inorganic materials. Examples of fillers used in this invention include metal carbonates (e.g., calcium carbonate (e.g., chalk, limestone, limestone, white limestone, marble, and limestone), magnesium carbonate, sodium carbonate, magnesium carbonate), silicon oxide (e.g. quartz , glass beads, hollow glass beads and fiberglass), silicates (e.g. talc, clays (montmorillonite), feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate), metal sulfates (e.g. calcium sulfate, barium sulfate, sodium sulfate, sodium aluminum sulfate, aluminum sulfate), gypsum, vermiculite, wood flour, aluminum trihydrate, soot, metal oxides (e.g. calcium oxide (burnt lime), aluminum oxide, titanium dioxide) and metal sulfites (e.g. calcium sulfite).

Typically, the addition of a grinding aid increases the life of the abrasive product. Grinding intensifier is a material that has a significant effect on the chemical and physical grinding processes, improving operational characteristics. Although there is no theoretical basis, it is believed that grinding intensifier (s) (a) reduce friction between abrasive particles and the workpiece to be sanded, (b) prevent "clogging" of abrasive particles (i.e., prevent metal particles from welding on the tops of abrasive particles) or at least reduce the tendency to plaque in the upper portion of the abrasive particle, (c) reduce the temperature at the interface between the abrasive particles and the workpiece, or (d) reduce uyuschie efforts.

Grinding intensifiers cover a wide range of different materials and can be inorganic or organic in their basis. Examples of grinding enhancers include classes of chemical compounds such as waxes, organic halogenated compounds, salts of hydrohalic acids, and metals and their alloys. As a rule, organic halogen-containing compounds are destroyed during grinding with the release of hydrohalic acid or gaseous halide. Examples of such substances include chlorinated waxes, for example, tetrachloronaphthalene, pentachloronaphthalene and polyvinyl chloride. Examples of salts of hydrohalic acids include sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluorides, potassium chloride and magnesium chloride. Examples of metals include tin, lead, bismuth, cobalt, antimony, cadmium, and an alloy of iron with titanium. Other grinding enhancers include sulfur, sulfur-containing organic compounds, graphite and metal sulfides. The scope of the present invention also includes the use of a combination of different grinding intensifiers, which in some cases may have a synergistic effect. The preferred grinding enhancer is cryolite; the most preferred grinding intensifier is potassium tetrafluoroborate.

Grinding intensifiers, in particular, can be used in coated and bonded abrasive products. In coated abrasive products, the grinding enhancer is usually located in a supercoating binder layer deposited on the surface of the abrasive particles. However, sometimes an intensifier is added to the coating binder layer. Typically, the amount of grinding enhancer contained in coated abrasive products is about 50-300 g / m ² (preferably about 80-160 g / m ² ). In abrasive products with a vitreous binder, the grinding intensifier, as a rule, fills the pores of the product.

Abrasive articles may contain 100% abrasive particles in accordance with the present invention or a mixture of such abrasive particles with other abrasive particles and / or with dilution particles. However, the abrasive particles in accordance with the present invention should comprise at least 2 wt.%, Preferably at least 5 wt.%, And more preferably about 30-100 wt.% Of the amount of abrasive particles present in the abrasive article. In some cases, the abrasive particles in accordance with the present invention can be mixed with other abrasive particles and / or with diluent particles in a ratio ranging from 5 to 75 wt.%, From about 25 to 75 wt.%, About 40 to 60 wt.% or approximately 50/50 wt.% (i.e. in equal amounts by weight). Examples of suitable conventional abrasive particles include fused alumina (including white fused alumina, heat-treated alumina and brown alumina), silicon carbide, boron carbide, titanium carbide, diamond, cubic boron nitride, garnet, fused zirconia , abrasive particles obtained using sol-gel technology, etc. Abrasive particles obtained using sol-gel technology can be either sorted or unsorted. Similarly, abrasive particles obtained using sol-gel technology can have an arbitrary shape or their characteristic shape, for example, a rod or a trihedron. Examples of abrasive particles obtained using sol-gel technology include particles described in US patent No. 4314827 (Leitheiser and others), 4518397 (Leitheiser and others), 4623364 (Cottringer and others), 4744802 (Schwabel), 4770671 (Monroe and others), 4881951 (Wood and others), 5011508 (Wald and others), 5090968 (Pellow), 5139978 (Wood), 5201916 (Berg and others), 5227104 (Bauer), 5366523 (Rowenhorst et al.), 5429647 (Larmie), 5498269 (Larmie) and 5551963 (Larmie). Further detailed information regarding sintered alumina abrasive particles obtained using powdered alumina as raw material can be found, for example, in US Pat. Nos. 5,259,147 (Falz), 5,593,467 (Monroe) and 5,665,127 (Moltgen). Further detailed information regarding fused abrasive particles can be found, for example, in US Pat. Nos. 1 1161620 (Coulter), 1192709 (Tone), 1247337 (Saunders et al.), 1268533 (Allen), 2424645 (Baumann et al.), 3891408 (Rowse and others), 3781172 (Pett and others), 3893826 (Quinan and others), 4126429 (Watson), 4457767 (Poon and others), 5023212 (Dubots and others), 5143522 (Gibson and others .) and 5336280 (Dubots et al.), as well as in US applications having serial numbers 09/495978, 09/496422, 09/496638 and 09/496713, each of which was filed February 2, 2000, and 09/618876 , 09/618879, 09/619106, 09/619191, 09/619192, 09/619215, 09/619289, 09/619563, 09/619729, 09/619744 and 09/620262, each of which was filed July 19, 2000. , and 09/772730, filed January 30, 2001. In some cases, abrasive articles containing mixtures of abrasive particles have improved grinding characteristics compared to abrasive products containing one type of abrasive particles.

If there is a mixture of abrasive particles, then the types of particles forming it may have the same size. Alternatively, the types of abrasive particles may have different particle sizes. For example, abrasive particles in accordance with the present invention may be larger and other types of abrasive particles smaller. Conversely, abrasive particles in accordance with the present invention, for example, may be smaller, and other types of abrasive particles larger.

Examples of suitable diluent particles include marble, gypsum, flint, silica, iron oxide, aluminosilicate, glass (including hollow glass beads and glass beads), foam alumina, alumina beads and diluent agglomerates. The abrasive particles in accordance with the present invention can also be combined into abrasive agglomerates or with abrasive agglomerates. Abrasive agglomerate particles, as a rule, include a combination of abrasive particles, a binder and, optionally, additives. The binder may be an organic and / or inorganic substance. Abrasive agglomerates can have an arbitrary shape or their predetermined shape. The shape may be a bar, cylinder, pyramid, cone, square, etc. The size of the abrasive agglomerate particles typically varies from about 100 to 5000 micrometers, usually from about 250 to 2500 micrometers. Further detailed information regarding abrasive agglomerate particles can be found, for example, in US Pat. Christianson), as well as in U.S. applications serial numbers 09/688444 and 09/688484, filed October 16, 2000.

The abrasive particles can be uniformly distributed in the abrasive product or they can be concentrated in certain areas or fragments of the abrasive product. For example, a coated abrasive may consist of two layers of abrasive particles. The first layer contains abrasive particles other than the abrasive particles in accordance with the present invention, and the second (outer) layer contains abrasive particles in accordance with the present invention. Similarly, an abrasive with a binder may have two different sections of the grinding wheel. The outer section, in contrast to the inner, may include abrasive particles in accordance with the present invention. Alternatively, the abrasive particles in accordance with the present invention can be uniformly distributed throughout the binder abrasive product.

Further detailed information regarding coated abrasive products can be found, for example, in US Pat. Nos. 4,734,104 (Broberg), 4,737,163 (Larkey), 5,203,884 (Buchanan et al.), 5,152,917 (Pieper et al.), 5,378,251 (Culler and et al.), 5417726 (Stout et al.), 5436063 (Follett et al.), 5496386 (Broberg et al.), 5609706 (Benedict et al.), 5520711 (Helmin), 5954844 (Law et al.), 5961674 (Gagliardi et al.) And 5975988 (Christinason). Further detailed information regarding bonded abrasive products can be found, for example, in US Pat. Nos. 4,543,107 (Rue), 4,741,743 (Narayanan et al.), 4,800,685 (Haynes et al.), 4,898,597 (Hay et al.), 4,997,461 (Markhoff-Matheny and others), 5037453 (Narayanan and others), 5110332 (Narayanan and others) and 5863308 (Qi and others). Additional detailed information regarding abrasive products with a glassy binder can be found, for example, in US Pat. Nos. 4,543,107 (Rue), 4,898,597 (Hay et al.), 4,997,461 (Markhoff-Matheny et al.), 5,094,672 (Giles Jr. and etc.), 5118326 (Sheldon and others), 5131926 (Sheldon and others), 5203886 (Sheldon and others), 5282875 (Wood and others), 5738696 (Wu and others) and 5863308 (Qi). Further detailed information regarding nonwoven abrasive products can be found, for example, in US Pat. No. 2,985,593 (Hoover et al.).

The present invention provides a surface grinding method comprising contacting at least one abrasive particle in accordance with the present invention with a surface of a workpiece; and moving at least one of the elements of the abrasive particle or the contact surface, resulting in grinding of at least a portion of said surface with an abrasive particle. Abrasive grinding methods in accordance with the present invention range from abrasive grinding (i.e., removing a large part of the surface under high pressure) to polishing (for example, polishing medical implants with coated abrasive belts), and the latter method typically uses small abrasive particles (for example, having a discharge less than ANSI 220 and smaller). Abrasive particles can also be used for precision grinding, for example, for grinding cam shafts in circles with a glassy binder. Specialists in this field can easily determine the size of the abrasive particles used for a particular grinding method.

Abrasive grinding in accordance with the present invention can be dry or wet. Wet grinding can be carried out by spraying or in a continuous stream. Examples of commonly used fluids include water, water soluble oil, organic lubricating fluid, and emulsions. The liquid may serve to reduce heat generated during grinding and / or may act as a lubricant. The liquid may contain minor amounts of additives such as bactericides, anti-foaming agents, etc.

The abrasive particles in accordance with the present invention can be used for grinding such machined objects as aluminum metal objects, carbon steels, mild steels, tool steels, stainless steel, hardened steel, titanium, glass, ceramics, wood, wood-like materials, paint, painted surfaces, surfaces coated with organic material, etc. The applied grinding force typically varies from about 1 to 100 kilograms.

Glass ceramic options in accordance with the present invention can also be used for solid electrolytes, for example, in batteries with solid electrolyte, cells with solid oxide electrolyte and other electrochemical devices; carriers of radioactive waste and excess actinides; oxidation catalysts; oxygen sensors carriers of fluorescence centers; material for durable infrared transmission windows; and reinforcing materials. For example, it is known that the rare earth oxides of zirconium (Re ₂ Zr ₂ O ₇ ) of the pyrochlore type can be used in applications associated with the aforementioned radioactive waste and excess actinides, oxidation catalysts, oxygen monitoring sensors and fluorescence centers. Further, for example, it is known that Ce-containing mixed oxides are oxidation catalysts. Although there is no theoretical basis, it is believed that due to the redox properties and relatively high ability to accumulate oxygen, Ce-containing mixed oxides can help catalyze the oxidation reaction. Materials for a long-lasting infrared transmission window must withstand moisture, impacts of solid and liquid particles, high temperatures and fast heating speeds.

The advantages and embodiments of the present invention are further illustrated by the following examples, but the specific materials and their amounts given in these examples, as well as other conditions and details, should not be construed as excessively limiting the invention. All parts and percentages are given in mass fractions unless otherwise indicated. Unless otherwise specified, all examples do not contain significant amounts of SiO ₂ , B ₂ O ₃ , P ₂ O ₅ , GeO ₂ , TeO ₂ , As ₂ O ₃ and V ₂ O ₅ .

Examples

Examples 1-20

In a 250 ml polyethylene container (7.3 cm in diameter), 50 g of a mixture of various powders are loaded (as shown in Table 1 below, with sources of raw materials shown in Table 2), 75 g of isopropyl alcohol and 200 g of aluminum oxide grinding medium (cylindrical shape - both height and diameter are 0.635 cm; 99.9% aluminum oxide; obtained from Coors, Golden, CO). The contents of the polyethylene container are ground for 16 hours at 60 revolutions per minute (rpm). After grinding, the grinding media is removed and the suspension is poured into a warm (approximately 75 ° C.) glass pan (PYREX) and dried. The dried mixture is sieved through a 70 mesh sieve (hole size 212 micrometers) using a dye brush.

After grinding and sieving, the mixture of ground raw particles is slowly fed (0.5 g / min) into the flame of a hydrogen-oxygen burner to melt the particles. The burner used to melt the particles, resulting in melted droplets, is a Bethlehem PM2D type model burner supplied by Bethlehem Apparatus Co., Hellertown, PA. The flow rates of hydrogen and oxygen for the burner are as follows. For the inner ring, the hydrogen flow rate is 8 liters per minute, and the oxygen flow rate is 3.5 l / min. For the outer ring, the hydrogen flow rate is 23 l / min, and the oxygen flow rate is 12 l / min. The dried and particle-sized particles are slowly fed (0.5 g / min) into the burner flame, which melts the particles and carries them out into a 19-liter (5-gallon) cylindrical container (30 cm in diameter at 34 cm in height) with continuously circulating turbulent water to quickly quench fused drops. The angle at which the flame enters the water is approximately 45 °, and the length of the flame from the burner to the water surface is approximately 18 centimeters (cm). The resulting fused and rapidly quenched particles are collected and dried at 110 ° C. Particles are spherical in shape and vary in size from a few micrometers (i.e. microns) to 250 micrometers.

The percent yield of amorphous material is calculated from the resulting balls formed in the flame using a fraction of −100 + 120 mesh (i.e., a fraction collected between sieves with hole sizes of 150 micrometers and 125 micrometers). The measurements are carried out as follows. A single layer of balls is distributed on a glass slide. Balls are observed using an optical microscope. Using the crosshairs of an optical microscope eyepiece as a guide, balls that lie along a straight line are considered amorphous or crystalline depending on their optical purity. In total, 500 balls are counted, and the percent yield of amorphous material is determined by the number of amorphous balls divided by the total number of balls counted.

The materials obtained in examples 12-20 are amorphous, as determined by visual observation, but quantitative analysis in accordance with the above method is not carried out. An amorphous material is usually transparent due to the absence of light scattering centers, such as crystal boundaries, while crystalline particles have a crystalline structure and are opaque due to light scattering effects.

The phase of the mixture (vitreous / amorphous / crystalline) is determined by differential thermal analysis (DTA), as described below. A material is classified as amorphous if the corresponding DTA curve reflects an exothermic crystallization event (T _x ). If the same curve also reflects an endothermic event (T _g ) at a temperature below T _x , consider that it consists of a vitreous phase. If the DTA curve does not reflect such events, consider that it contains crystalline phases.

Differential thermal analysis (DTA) is carried out as follows. DTA data is obtained (using a device obtained from Netzsch Instruments, Selb, Germany, under the trade name "NETZSCH STA 409 DTA / TGA") using a fraction with a size of -140 + 170 mesh (i.e. a fraction collected between sieves with sizes holes between 105 micrometers and 90 micrometers). The amount of each sieved sample placed in a 100 μl Al ₂ O ₃ sample holder is approximately 400 milligrams. Each sample is heated in static air at a rate of 10 ° C / min from room temperature (approximately 25 ° C) to 1100 ° C.

As shown in FIG. 4, line 123 is a graphical DTA data for the material of Example 1. On line 123 of Figure 4, an endothermic event occurs at a temperature of approximately 872 ° C., as indicated by a downward curve of line 123. It is believed that this the event occurs due to the glass transition (T _g ) of the glassy material. An exothermic event is observed at a temperature of approximately 958 ° C., as evidenced by the sharp peak on line 123. It is believed that this event occurs due to crystallization (T _x ) of the material. These values of T _g and T _x for other samples, except for samples of examples 15-20, are presented below in Table 1.

Example 21

Approximately 25 grams of the balls from Example 1 are placed in a graphite mold and hot stamped using a single screw pressing device (obtained under the trade name "HP-50", Thermal Technology Inc., Bree, Calif.). Hot stamping is carried out in an argon atmosphere at a pressure of 13.8 megapascals (MPa) (2000 pounds per square inch). The hot stamping furnace is heated in a gradient to 970 ° C at 25 ° C / min. The result is a circle with a diameter of 3.4 cm and a thickness of 0.6 cm of a transparent base material. DTA research is carried out as described in example 1-20. The endothermic event at a temperature of approximately 885 ° C is shown on the curve, as indicated by a downward change in the curve. It is believed that this event occurs due to the glass transition (T _g ) of the glassy material. At a temperature of approximately 928 ° C, the same material gives an exothermic event, as evidenced by a sharp peak in the curve. It is believed that this event occurs due to crystallization (T _x ) of the material.

Example 22

In a 250 ml polyethylene container (7.3 cm diameter), 50 g of the following mixture are charged: 19.3 g of alumina particles (obtained from Alcoa Industrial Chemicals, Bauxite, Arkansas, under the trade designation A16SG), 9.5 g of particles zirconium oxide (obtained from Zirconia Sales, Inc. of Marietta, Georgia, under the trade designation DK-2) and 21.2 grams of lanthanum oxide particles (obtained from Molycorp Inc., Mountain Pass, California), 75 g of isopropyl alcohol and 200 g of alumina grinding medium (cylindrical shape, both height and diameter are 0.635 cm; 99.9% alumina; obtained from Coors, Golden, pc. K olorado). The contents of the polyethylene container are ground for 16 hours at 60 revolutions per minute (rpm). The ratio of alumina to zirconia in the starting material is 2: 1, and alumina and zirconium together are approximately 58 wt.%. After grinding, the grinding media is removed and the suspension is poured into a warm (approximately 75 ° C.) glass pan (PYREX) and dried. The dried mixture is sieved through a 70 mesh sieve (hole size 212 micrometers) using a dye brush.

After grinding and sieving, the mixture of ground raw particles is slowly fed (0.5 g / min) into the flame of a hydrogen-oxygen burner to melt the particles. The burner used for the particle smelting process, in which fused droplets form, is a Bethlehem PM2D type table burner, Model B, supplied by Bethlehem Apparatus Co., Hellertown, pc. Pennsylvania. The flow rates of hydrogen and oxygen for the burner are as follows. For the inner ring, the hydrogen flow rate is 8 l / min, and the oxygen flow rate is 3.5 l / min. For the outer ring, the hydrogen flow rate is 23 l / min, and the oxygen flow rate is 12 l / min. The dried and particle-sized particles are slowly fed (0.5 g / min) into the burner flame, which melts the particles and carries them out onto a sloping stainless steel surface (approximately 51 cm (20 inches)) at an angle of incidence of 45 degrees with cold water flowing over the surface (approximately 8 l / min) to quickly quench fused drops. The resulting fused and quenched particles are collected and dried at 110 ° C. Particles are spherical in shape and vary in size from a few micrometers (i.e. microns) to 250 micrometers.

Subsequently, balls formed in a flame having diameters of less than 125 micrometers are passed through a plasma gun and deposited on stainless steel substrates as follows.

Four substrates of stainless steel 304 (with dimensions of 76.2 mm (mm) × 25.4 mm × 3.175 mm) and two substrates of carbon steel 1080 (76.2 mm × 25.4 mm × 1.15 mm) are obtained as follows way. The sides to be coated are treated with a sand jet, washed in an ultrasonic bath, and then wiped clean with isopropyl alcohol. Four stainless steel substrates and one carbon steel 1080 are placed at a distance of approximately 10 centimeters (cm) in front of the plasma gun nozzle (obtained under the trade designation “Praxair SG-100 Plasma Gun” from Praxair Surface Technologies, Concord, New Hampshire) . A second substrate of carbon steel 1080 is placed at a distance of 18 cm in front of the plasma gun nozzle. Coatings made on second samples of carbon steel 1080 at a distance of 18 cm in front of the plasma gun nozzle are not further described.

The plasma unit has a power of 40 kW. Plasma gas is argon (50 psi), 0.3 megapascal (MPa) with helium as auxiliary gas (150 psi, 1 MPa). Balls are passed through a plasma gun using argon as a carrier gas (50 psi, 0.3 MPa) using a Praxair model 1270 computerized powder feeder (obtained from Praxair Surface Technologies, Concord, NJ) . During deposition, a voltage of approximately 40 volts and a current of approximately 900 amps are applied, and the plasma gun is panned from left to right, up and down to evenly coat the substrates. When the desired thickness is reached, plasma spraying is stopped and the samples regenerate. The carbon steel substrate 1080 is bent, thereby separating the coating from the substrate, resulting in a free-standing base material. The deposited material has a size z (thickness) of approximately 1350 micrometers as determined using optical microscopy.

The phase of the mixture (vitreous / amorphous / crystalline) is determined by differential thermal analysis (DTA), as described below. A material is classified as amorphous if the corresponding DTA curve reflects an exothermic crystallization event (T _x ). If the same curve also reflects an endothermic event (T _g ) at a temperature below T _x , consider that the substance consists of a glass phase. If the DTA curve does not reflect such events, consider that the substance contains crystalline phases.

Differential thermal analysis (DTA) is carried out using the following method. DTA data is obtained (using a device obtained from Netzsch Instruments, Selb, Germany, under the trade designation "NETZSCH STA 409 DTA / TGA") using a fraction of size -140 + 170 mesh (ie, a fraction collected between sieves with hole sizes between 105 micrometers and 90 micrometers). The amount of each sifted sample placed in a 100 μl Al ₂ O ₃ sample holder is approximately 400 milligrams. Each sample is heated in static air at a speed of 10 ° C / min from room temperature (approximately 25 ° C) to 1100 ° C.

The coated material (on 304 stainless steel substrates) represents an endothermic event at a temperature of approximately 880 ° C, as indicated by a downward change in the recording curve. It is believed that this event occurs due to the glass transition (T _g ) of the glassy material. The same material exhibits an exothermic event at a temperature of approximately 931 ° C, as evidenced by a sharp peak in the curve. It is believed that this event occurs due to crystallization (T _x ) of the material. Thus, the coated material (on stainless steel substrates 304) and the free-standing base material are glassy, as determined by DTA.

A part of the vitreous free-standing base material is then subjected to heat treatment at 1300 ° C. for 48 hours. To determine the phases present, X-ray powder diffraction is used (using an X-ray diffractometer (obtained under the trade designation "PHILLIPS XRG 3100" from Phillips, Machwah, NJ) with Kα1 radiation of copper 1.54050 angstroms)). The phases are determined by comparing the peaks present in the XRD image of the crystallized material with X-ray diffraction patterns of the crystalline phases presented in the JCPDS (Joint Committee on Powder Diffraction Standards) databases published by the International Center for Diffraction Data. The resulting crystalline material includes LaAlO ₃ , ZrO ₂ (cubic, tetragonal), LaAl ₁₁ O ₁₈ and transition phases Al ₂ O ₃ .

Another portion of the glassy free-standing base material is crystallized at 1300 ° C. for 1 hour in an electric heating furnace (obtained from CM Furnaces, Bloomfield, NJ, under the trade designation “Rapid Temp Furnace”). The crystallized coating is crushed with a hammer into particles with a size of -30 + 35 mesh (i.e., the fraction collected between sieves with openings of 600 and 500 micrometers). The particles are cleaned of splinters by washing in an ultrasonic bath (obtained from Cole-Parmer, Vernon Hills, Ill., Under the trade designation "8891") for 15 minutes, dried at 100 ° C and several particles are mounted on a metal cylinder (3 cm in diameter) and 2 cm high) using carbon tape. An established sample is coated with a thin layer of gold-palladium and observed using JEOL scanning electron microscopy (SEM) (model JSM 840A). The fault surface is rough and no more than 200 nanometers (nm) crystals were present in the SEM (Fig. 5).

Example 23

Starting particles were prepared as described in Example 22 using the following 50 gram mixture: 21.5 grams of alumina particles (obtained from Alcoa Industrial Chemicals, Bauxite, Arkansas, under the trade designation A16SG), 9 grams of zirconia particles (obtained from Zirconia Sales, Inc. of Marietta, Georgia, under the trade designation DK-2) and 19.5 grams of cerium oxide particles (obtained from Rhone-Poulence, France). The ratio of alumina to zirconia in the starting material is 2.4: 1, and alumina and zirconia together are approximately 61 wt.%. The starting particles are formed in a flame into balls (the size of which varies from a few micrometers to 250 micrometers), as described in Example 22. Subsequently, balls formed in a flame having diameters between 180 and 250 micrometers are passed through a plasma gun and deposited on stainless substrates. and carbon steel, as described in example 22.

The carbon steel substrates 1080 are bent, thereby separating the coating from the substrate, resulting in a free-standing base material. The resulting base material has a size z (thickness) of approximately 700 micrometers, as determined using optical microscopy. The microstructure is also observed using optical microscopy. The material consists, as a rule, of spherical and inclined crystalline particles, which are opaque, mainly in an amorphous matrix, which is transparent. An amorphous material is usually transparent due to the absence of light scattering centers, such as crystal boundaries, while crystalline particles exhibit a crystalline structure and are opaque due to light scattering effects. The crystalline phases determined by the analysis of the RD of the powder, as described in Example 22, consist of Zr _0.4 Ce _0.6 O ₂ (cubic) and transition Al ₂ O ₃ .

A second deposition experiment is carried out using flame formed beads having diameters of less than 125 micrometers. The resulting coating has a size z (thickness) of approximately 1100 micrometers, as determined using optical microscopy. The microstructure is also observed using optical microscopy. This material has similar characteristics (i.e., it consists, as a rule, of spherical and inclined crystalline particles in a mainly amorphous matrix) with those materials that are formed from balls having a diameter between 180 and 250 micrometers. The crystalline phases determined by analysis of the RD of the powder, as described in Example 22, consist of Zr _0.4 Ce _0.6 O ₂ (cubic) and transition Al ₂ O ₃ .

The average hardness of the atomized material of this example is determined as follows. Slices of material are set in a base resin (obtained under the trade name "TRANSOPTIC POWDER" from Buehler Ltd., Lake Bluff, Illinois). The resulting resin cylinder is approximately 2.5 cm in diameter and approximately 1.9 cm in height. An established slice is prepared using a traditional polishing technique using a polisher (obtained from Buehler, Lake Bluff, Illinois, under the trade designation "ECOMET 3"). The sample is polished for approximately 3 minutes using a diamond wheel, followed by 5 minutes polishing of each of 45, 30, 15, 9, 3 and 1 micrometer suspension. Microhardness measurements are carried out using a conventional microhardness meter (obtained under the trade name "MITUTOYO MVK-VL" from Mitutoyo Corporation, Tokyo, Japan) equipped with a Vickers indenter using a 100 gram tip load. Microhardness measurements are carried out in accordance with the instructions set forth in ASTM Test Method E384 Test Methods for Microhardness of Materials (1991). The average microhardness (average result of 20 measurements) of the material of this example is 15 gigapascals (GPa).

Example 24

The starting particles were prepared as described in Example 22 using the following 50 gram mixture: 27.9 grams of alumina particles (obtained from Alcoa Industrial Chemicals, Bauxite, Arkansas, under the trade designation A16SG), 7.8 grams of zirconia particles (obtained from Zirconia Sales, Inc. of Marietta, Georgia, under the trade designation DK-2) and 14.3 grams of yttrium oxide particles (obtained from N.C. Stark Newton, Mass.). The ratio of alumina to zirconia in the original starting material is 3.5: 1, and alumina and zirconia together are approximately 72 wt.%. The starting particles are further sieved through a 30 mesh sieve (opening size 600 μm) and heat treated at 1400 ° C. for 2 hours in an electric heating furnace (obtained from CM Furnaces, Bloomfield, NJ, under the trade designation “Rapid Temp Furnace "). The heat-treated particles are further sieved to separate particles with diameters between 125 and 180 micrometers, which are then passed through a plasma gun and deposited on stainless steel substrates, as described in example 22.

The carbon steel substrates 1080 are bent, thereby separating the coating from the substrate, resulting in a free-standing base material. The resulting base material has a size z (thickness) of approximately 700 micrometers, as determined using optical microscopy. The microstructure is also observed using optical microscopy. The material consists mainly of crystalline opaque particles (which retain their original forms), mainly in a transparent amorphous matrix. The crystalline phases determined by analysis of the RD of the powder, as described in Example 22, consist of Al ₅ Y ₃ O ₁₂ and Y _0.15 Zr _0.85 O _1.93 .

Another portion of the free-standing base material is crystallized at 1300 ° C. for 1 hour, and the fracture surface is sprayed with a thin layer of gold-palladium and observed using JEOL SEM (Model JSM 840A) as described above in Example 22. The fracture surface is rough , and crystals larger than 200 nanometers (nm) are not present (Figure 6).

A second precipitation experiment was carried out using heat-treated particles having diameters of less than 125 micrometers. The resulting coating has a thickness of approximately 1,500 micrometers (size z). The microstructure is studied using optical microscopy. This material has similar characteristics (i.e., it consists, as a rule, of opaque, crystalline particles (which retain their original shapes), mainly in a transparent, amorphous matrix) with those materials that are formed from balls having a diameter in the range between 180 and 250 micrometers. The crystalline phases determined by analysis of the RD of the powder, as described in Example 22, consist of Al ₅ Y ₃ O ₁₂ and Y _0.15 Zr _0.85 O _1.93 .

Example 25

The thickened coating, consisting of various layers of the above three examples, is treated by plasma spraying using the starting particles obtained in examples 22-24. The first layer is coated as described in example 23, the second, as described in example 22, and the third, as described in example 24.

The substrate is not treated with a sand stream before coating, so that it is easily removed by peeling by hand, which leads to a free-standing base material with dimensions of approximately 75 millimeters (mm) × 25 mm × 7.5 mm. The cross section during cutting of each layer is separated from the material using a diamond saw. The separated piece is set in a base resin (obtained under the trade name "TRANSOPTIC POWDER" from Buehler Ltd., Lake Bluff, Illinois) so that the various layers are visible. The resulting resin cylinder is approximately 2.5 cm in diameter and approximately 1.9 cm in height. An established slice is prepared using a traditional polishing technique using a polisher (obtained from Buehler, Lake Bluff, Illinois, under the trade designation "ECOMET 3"). The sample is polished for approximately 3 minutes using a diamond wheel, followed by 5 minutes polishing of each of 45, 30, 15, 9, 3 and 1 micrometer suspension.

The first layer has a size z (thickness) of approximately 2.5 mm, as determined using optical microscopy. The microstructure is observed using optical microscopy. This material has similar characteristics with those of Example 23 (i.e., consists mainly of spherical and opaque crystalline particles, mainly in a transparent amorphous matrix). The second layer has a size z (thickness) of approximately 2 mm, as determined using optical microscopy. The microstructure is also observed using optical microscopy. This material has similar characteristics with those of Example 22 (i.e., it is transparent, which suggests that it is amorphous). The third layer has a size z (thickness) of approximately 3 mm, as determined using optical microscopy. The microstructure is also observed using optical microscopy. This material has similar characteristics to those of Example 24 (i.e., it consists mainly of opaque crystalline particles (which retain their original shapes), mainly in a transparent amorphous matrix).

Example 26

The consolidated material obtained in Example 21 is crushed using a Chipmunk jaw crusher (Type VD, manufactured by BICO Inc., Burbank, Calif.) To abrasive particles and sorted to a -30 + 35 mesh fraction (i.e. the fraction collected between sieves with openings of 600 and 500 micrometers) and the -35 + 40 mesh fraction (i.e., the fraction collected between sieves with openings of 500 and 425 micrometers). These two mesh fractions are combined to form a 50/50 mixture.

The average aspect ratio (width to length ratio) for particles is measured using a Zeiss Image Analysis System (Zeiss Stemi SV11 microscope and computer software) and a video camera (CCD camera 3, model 330, (obtained from Dage MTI Inc ., Michigan City, Indiana)). The resulting ratio of width to length is 1.86.

Particle density was measured using an AccuPyc 1330 gas pycnometer, Micrometrics, Norcross, pc. Georgia. The resulting density is 4.65 grams per cubic centimeter (g / cm ³ ).

The crushed particles are heat-treated at 1300 ° C. for 45 minutes in an electric-heated furnace (obtained from CM Furnaces, Bloomfield, NJ, under the trade designation “Rapid Temp Furnace”). The resulting crystalline particles retain their original fragmented shape. The particle density is 5.24 grams per cubic centimeter (g / cm ³ ). The crystalline glass-ceramic phases determined by the RD analysis as described in Examples 1-20 consist of LaAlO ₃ , cubic / tetragonal ZrO ₂ , LaAl ₁₁ O ₁₈ , α-Al ₂ O ₃ , monoclinic ZrO ₂ and minor amorphous phases.

Example 27-28

19.3 g of alumina particles (obtained from Alcoa Industrial Chemicals, Bauxite, Arkansas, under the trade designation A16SG), 9.5 g of zirconia particles (obtained from Zirconia Sales, Inc. of Marietta, Georgia, under the trade designation “DK-2”) and 21.2 grams of lanthanum oxide particles (obtained from Molycorp Inc., Mountain Pass, California), 75 g of isopropyl alcohol and 200 g of grinding medium of aluminum oxide (cylindrical shape, both height and diameter are 0.635 cm; 99.9% aluminum oxide; obtained from Coors, Golden, Colorado). The contents of the polyethylene container are ground for 16 hours at 60 revolutions per minute (rpm). After grinding, the grinding medium is removed and the suspension is poured into a warm (approximately 75 ° C.) glass pan (PYREX) and dried for 3 minutes. The dried mixture is sieved through a sieve with 14 mesh (hole size 1400 micrometers) using a dye brush and pre-sintered at 1400 ° C in air for two hours.

A hole is drilled at the end of a graphite rod (approximately 60 cm long, 15 mm in diameter) (approximately 13 mm in diameter, approximately 8 cm deep). About 20 grams of pre-sintered particles are introduced into the hollow end. The hollow end of a graphite rod is introduced into the hot zone of a resistance furnace (obtained from Astro Industries, Santa Barbara, Calif.). The furnace is modified to convert it into a graphite tube tube furnace with an inner diameter of approximately 18 mm. The hot zone is maintained at a temperature of 2000 ° C. and the furnace is tilted at an angle of approximately 30 ° so that the melt does not pour out of the rod. The end of the rod is kept in the hot zone for 10 minutes to ensure uniform melting. After 10 minutes, the rod is quickly removed from the furnace and tilted to pour the melt onto the quench surface.

For example 27, the blanking surface represents two opposing stainless steel plates. Plates of 17.8 cm × 5 cm × 2.5 cm are placed with long ends parallel to each other with a gap of approximately 1 mm. The melt is poured into the gap, where it quickly solidifies in the form of a plate with a size z (thickness) of approximately 1 mm. The quenched melt is substantially transparent and amorphous and has a glass transition temperature (T _g ) of 885 ° C and a crystallization temperature (T _x ) of 930 ° C, as determined by the DTA curve obtained as described in Examples 1-20.

For example 28, the blanking surface represents two steel rollers rotating in opposite directions. The rollers are 5 cm in diameter and are driven by an electric motor at 80 rpm. The clearance between the rollers is approximately 0.8 mm. The melt is poured into the gap, where the rollers quickly solidify into a plate with significant dimensions x and y and a size z (thickness) of 0.8 mm. The quenched melt is substantially transparent and amorphous and has a glass transition temperature (T _g ) of 885 ° C and a crystallization temperature (T _x ) of 930 ° C, as determined by the DTA curve obtained as described in Examples 1-20.

Example 29

The base amorphous / vitreous material obtained in Example 21 is crushed using a Chipmunk jaw crusher (Type VD, manufactured by BICO Inc., Burbank, Calif.) To abrasive particles and sorted for -30 + 35 mesh fractions (t i.e., the fraction collected between sieves with openings of 600 and 500 micrometers) and the -35 + 40 mesh fraction (i.e. the fraction collected between sieves with openings of 500 and 425 micrometers). These two mesh fractions are combined to form a 50/50 mixture.

The measurement of the ratio of width to length is carried out using the method of example 26. The resulting ratio of width to length is 1.83.

The density of the particles is measured using the method of example 26. The resulting density is 4.61 g / cm ³ .

Examples 30-31

A hot stamping disc was prepared as described in Example 21 and divided into 2 strips (approximately 2 cm × 0.5 cm × 0.5 cm) using a diamond file (obtained from Buehler, Lake Bluff, Illinois, under trade designation "ISOMET 1000"). Both strips are annealed in an electrically heated oven (obtained from CM Furnaces, Bloomfield, NJ, under the trade name Rapid Temp Furnace) at 800 ° C. for 2 hours. During the annealing process, crystallization does not occur.

For example 30, one strip is crushed with a hammer into particles with a size of -30 + 35 mesh (i.e. the fraction collected between sieves with openings of 600 and 500 micrometers). Crushed particles are heat treated at 1300 ° C. for 1 hour in an electric heating furnace (obtained from CM Furnaces, Bloomfield, NJ, under the trade designation “Rapid Temp Furnace”) to crystallize them. The particles are cleaned of splinters by washing in an ultrasonic bath (obtained from Cole-Parmer, Vernon Hills, Ill., Under the trade designation "8891") for 15 minutes, dried at 100 ° C and several particles are mounted on a metal cylinder (diameter 3 cm and a height of 2 cm) using carbon tape. An established sample is coated with a thin layer of gold-palladium and observed using JEOL scanning electron microscopy (SEM) (Model JSM 840A).

In the material of example 30, the classical characteristics of the destruction of glass are noticeable, even after crystallization occurs. The fault surface shown in FIG. 7 is a good example of Wallner lines common to most glass fracture cases. The fault surface shown in Fig. 8 has a cleavage, another common characteristic of glass fracture. The definitions of Wallner and Notch lines are taken from the Fundamentals of Inorganic Glasses textbook. Arun K Varshneya, pp. 425-27, 1994.

The average hardness of the material of example 30 is determined as follows. Several particles are set in a base resin (supplied under the trade name "TRANSOPTIC POWDER" from Buehler Ltd., Lake Bluff, Illinois). The resulting resin cylinder is approximately 2.5 cm in diameter and approximately 1.9 cm in height. An established slice is prepared using a traditional polishing technique using a polisher (obtained from Buehler, Lake Bluff, Illinois, under the trade designation "ECOMET 3"). The sample is polished for approximately 3 minutes using a diamond wheel, followed by 5 minutes polishing of each of 45, 30, 15, 9, 3 and 1 micrometer suspension. Microhardness measurements are performed using a conventional microhardness meter (supplied under the trade name "MITUTOYO MVK-VL" from Mitutoyo Corporation, Tokyo, Japan) equipped with a Vickers indenter using a 500 gram tip load. Microhardness measurements are carried out in accordance with the instructions set forth in ASTM Test Method E384 Test Methods for Microhardness of Materials (1991). The average microhardness is the average of 20 measurements. The average microhardness of the material of example 30 is 16.4 gigapascals (GPa).

For Example 31, the second half of the strip was heat-treated at 1300 ° C for 1 hour in an electric-heated furnace (obtained from CM Furnaces, Bloomfield, NJ, under the trade designation "Rapid Temp Furnace"). The heat-treated strip is crushed with a hammer into particles with a size of -30 + 35 mesh (i.e., the fraction collected between sieves with openings of 600 and 500 micrometers). Particles are set and observed using the above methods.

In contrast to the glass fracture surface of the material of Example 30, the material of Example 31 represents fault surfaces generally visible in a polycrystalline material. The fracture surface shown in Example 9 shows a rough surface with a feature similar in size to the crystal size typical of a transgranular fracture.

Example 32

The balls from example 4 are subjected to heat treatment at 1300 ° C for 30 minutes in an electric heating furnace. The crystallized beads are mounted and polished as described in Examples 30-31 and coated with a thin layer of gold-palladium and observed using JEOL SEM (Model JSM 840 A). Figure 10 is a typical electron backscattering (BSE) micrograph of a microstructure found in crystallized beads. The crystallized sample is nanocrystalline with a very narrow crystal size distribution, and crystals larger than 200 nm cannot be visually observed from the micrograph.

The average crystal size is determined by the line crossing method in accordance with ASTM E112-96 "Standard Test Methods for Determining Average Grain Size". The sample is set in a base resin (obtained under the trade name "TRANSOPTIC POWDER" from Buehler Ltd., Lake Bluff, Illinois). The resulting polymer cylinder is approximately 2.5 cm in diameter and approximately 1.9 cm in height. An established slice is prepared using a traditional polishing technique using a polisher (obtained from Buehler, Lake Bluff, Illinois under the trade designation "ECOMET 3"). The sample is polished for approximately 3 minutes using a diamond wheel, followed by 5 minutes polishing of each of 45, 30, 15, 9, 3 and 1 micrometer suspension. An established and polished sample is coated with a thin layer of gold-palladium and observed using JEOL SEM (Model JSM 840 A). A typical electron backscattering (BSE) micrograph of the microstructure found in the sample is used to determine the average crystal size as follows. The number of crystals that cross the unit of length (N _L ) of a random line drawn across the micrograph is counted. The average crystal size is determined by a given number using the following equation:

where N _L represents the number of crystals crossing a unit of length, and M represents an increase in micrograph. The average crystal size of the sample is 140 nm, as measured by the line crossing method.

Example 33

The consolidated material obtained in Example 21 was heat treated at 1300 ° C. for 45 minutes in an electric heating furnace (obtained from CM Furnaces, Bloomfield, NJ, under the trade designation “Rapid Temp Furnace”). The resulting crystalline material is crushed using a Chipmunk jaw crusher (Type VD, manufactured by BICO Inc., Burbank, Calif.) To abrasive particles and sorted to collect a −30 + 35 mesh fraction (i.e., fraction collected between sieves with openings of 600 and 500 micrometers) and a -35 + 40 mesh fraction (i.e., the fraction collected between sieves with openings of 500 and 5425 micrometers). These two mesh fractions are combined to form a 50/50 mixture.

The measurement of the ratio of width to length is carried out using the method of example 26. The resulting ratio of width to length is 1.84.

The particle density is measured using the method of example 26. The resulting density is 5.19 g / cm ³ .

Example 34

Approximately 150 grams of the pellets obtained as described in Example 1 are placed in a steel container with dimensions of 5 centimeters (cm) × 5 cm × 5 cm, which is then evacuated and sealed. The steel container is then subjected to hot isostatic pressing (HIP) using a HIP device (obtained under the trade name "IPS Eagle-6", American Isostatic Pressing, Ohio). HIP is carried out at a pressure of 207 MPa in an argon atmosphere. The HIP furnace is heated to 970 ° C at a rate of 25 ° C / min and kept at this temperature for 30 minutes. After completion of the HIP, the steel is cut and the loading material is removed. Observe the coalescence of the balls with the formation of a single mass of transparent glassy material. According to the DTA curve, carried out as described in examples 1-20, it is determined that the glass transition temperature (T _g ) is 879 ° C and the crystallization temperature (T _x ) is 931 ° C.

Example 35

819.6 grams of alumina particles ("ARA-0.5"), 818 grams of lanthanum particles (obtained from Molycorp, Inc.), 362.4 grams of yttrium stabilized zirconia particles (with a nominal composition) are loaded into a mill with polyurethane guides 94.6 wt.% ZrO ₂ (+ HfO ₂ ) and 5.4 wt.% Y ₂ O ₃ ; obtained under the trade name "HSY-3" from Zirconia Sales, Inc. of Marietta, Georgia), 1050 grams distilled water and approximately 2000 grams of zirconium oxide grinding media (obtained from Tosoh Ceramics, Division of Bound Brook, NJ, under the trade designation "YTZ"). The mixture is ground at 120 revolutions per minute (rpm) for 4 hours until the ingredients are fully mixed. After grinding, the medium is removed and the suspension is poured onto a glass tray (PYREX), where it is dried using a jet dryer. The dried mixture is ground using a mortar and pestle and sieved through a 70 mesh sieve (hole size 212 micrometers). After grinding and sieving, some particles are placed in the flame of a hydrogen-oxygen burner, as described in example 22.

Approximately 50 grams of the pellets are placed in a graphite mold and hot pressed using a uniaxial pressure generating device (obtained under the trade name "HP-50", Thermal Technology Inc., Bree, Calif.). Hot pressing is carried out at 960 ° C in an argon atmosphere at a pressure of 13.8 megapascals (MPa) (2000 psi). The resulting translucent circle has a diameter of approximately 48 millimeters and a thickness of 5 mm. Conduct additional cycles of hot pressing, receiving other disks. Figure 11 shows an optical micrograph of a slice (2 mm thick) of the material obtained by hot pressing, showing the transparency of the material.

The density of the glassy material obtained by hot pressing, measured by the method of Archimedes, is in the range of about 4.1-4.4 g / cm ³ . The Young's modulus (E) of the hot-pressed glassy material, measured using an ultrasound analysis system (obtained from Nortek, Richland, Wash., Under the trade designation "NDT-140"), is in the range of about 130-150 GPa.

The average microhardness obtained by hot pressing the material is determined as follows. Pieces of the hot-pressed material (approximately 2-5 millimeters in size) are set in the base resin (obtained under the trade name "EROMET 3" from Buehler Ltd., Lake Blufff, Illinois). The final resin cylinder has a diameter of approximately 2.5 cm (1 inch) and a height of approximately 1.9 cm (0.75 inches). Installed samples are polished using a conventional grinding / polishing device (obtained under the trade name "EPOMET 3" from Buehler Ltd.) and traditional diamond suspensions, and in the last stage of polishing, a diamond suspension with a particle size of 1 micrometer (obtained under the trade name "METADI "from Buehler Ltd.), obtaining polished sections of the sample.

Microhardness measurements are carried out using a traditional microhardness meter (obtained under the trade name "MITUTOYO MVK-VL" from Mitutoyo Corporation, Tokyo, Japan) equipped with a Vickers indenter using a 500 gram tip load. Microhardness measurements are carried out in accordance with ASTM Test Method E384 Test Methods for Microhardness of Materials (1991). The microhardness value is determined as the average of 20 measurements. The average microhardness of the material obtained by hot pressing is 8.3 gigapascals (GPa).

The average value of the indentation strength of the hot-pressed material is calculated by measuring the length of the crack propagating from the tip of the indent from the Vickers indenter obtained using the microhardness measuring device (obtained under the trade name "MITUTOYO MVK-VL" from Mitutoyo Corporation, Tokyo, Japan) with load of 500 grams. The indentation strength (K _IC ) is calculated by the equation:

K _IC = 0.016 (E / H) ^1/2 (P / c) ^3/2 ,

where E = Young's modulus of a given material;

H = Vickers strength;

P = indenter force in Newtons;

c = crack length from the center of the dent to its end.

Samples for measuring toughness are obtained as described above for microhardness analysis. The resulting indentation strengths are the average of 5 measurements. The length of the crack (s) is measured with a digital caliper on micrographs obtained using a scanning electron microscope ("JEOL SEM" (model JSM 6400)). The average value of the indentation strength obtained by hot pressing of the material is 1.4 MPa-m ^1/2 .

The thermal expansion coefficient of the hot-pressed material is measured using a thermal analyzer (obtained from Perkin Elmer, Shelton, Connecticut, under the trade designation "PERKIN ELMER THERMAL ANALYSER"). The average value of the coefficient of thermal expansion is 7.6 × 10 ^-6 / ° C.

The thermal conductivity of the hot-pressed material is measured in accordance with ASTM standard "D 5470-95, Test Method A" (1995). The average value of thermal conductivity is 1.15 W / m · K.

The semi-transparent circle obtained by hot pressing glass based on La ₂ O ₃ -Al ₂ O ₃ -ZrO _{2 is} subjected to heat treatment in an electric furnace (obtained under the trade name "Model KKSK-666-3100" from Keith Furnacesof Pico Rivera, pc. California) as follows way. Initially, the circle is warmed from room temperature (approximately 25 ° C.) to approximately 900 ° C. at a rate of 10 ° C./min and then held at 900 ° C. for approximately 1 hour. The circle is then heated from approximately 900 ° C. to approximately 1300 ° C. at a rate of approximately 10 ° C./min, then held at 1300 ° C. for approximately 1 hour, after which it is cooled to room temperature by rotating the oven. Conduct additional cycles of heat treatment in the same way, getting other circles.

12 is a scanning electron microscope (SEM) micrograph of a polished section obtained by heat treatment of the material of Example 35, showing the fine crystalline nature of the material. A polished slice is prepared using traditional installation and polishing methods. Polishing is performed using a polishing device (obtained from Buehler, Lake Bluff, Illinois, under the trade designation "ECOMET 3 TYPE POLISHER-GRINDER"). The sample is polished for approximately 3 minutes with a diamond wheel, then approximately three minutes for each of the diamond suspensions containing particles of sizes 45, 30, 15, 9 and 3 micrometers. A polished sample was coated with a thin layer of palladium gold alloy and observed using JEOL SEM (model JSM 840A).

Based on the data of X-ray powder diffractometry, as described in Example 22, a sample obtained by heat treatment of the material of Example 35, and analysis of a polished sample using SEM in backscattering mode, it is believed that the dark areas in the micrograph correspond to LaAl ₁₁ O ₁₈ crystals; gray areas to LaAlO crystals ₃ , and white portions of cubic / tetragonal ZrO ₂ .

The density of the material obtained by heat treatment, measured by the method of Archimedes, is approximately 5.18 g / cm ³ . The Young's modulus (E) of the heat-treated material measured using an ultrasonic analysis system (obtained from Nortek, Richland, Wash., Under the trade designation "NDT-140") is approximately 260 GPa. The average microhardness value obtained by heat treatment of the material, determined according to the above, for the glass balls of example 35 method, is 18.3 GPa. The average value of resistance to cracking (K _ic ) obtained by heat treatment of the material, determined according to the method described above for the hot-pressed material of example 35, is 3.3 MPa · m ^1/2 .

Examples 36-38

Balls of examples 36-38 receive, as described in example 35, except that the raw materials and quantities of raw materials used are shown in Table 3 below, and the grinding of raw materials is carried out in 90 milliliters (ml) of isopropyl alcohol with 200 grams of zirconium oxide medium (obtained from Tosoh Ceramics, a division of Bound Brook, NJ, under the trade name "YTZ") at 120 rpm for 24 hours. Sources of raw materials used are shown in Table 4 below.

Table 3 Example Percentage by weight of components Boot quantities, g 36 ^* La ₂ O ₃ : 48 La ₂ O ₃ : 240 Al ₂ O ₃ : 52 Al ₂ O ₃ : 260 37 Al ₂ O ₃ : 41.0 Al ₂ O ₃ : 20.5 ZrO ₂ : 18.0 ZrO ₂ : 9.0 Gd ₂ O ₃ : 41.0 Gd ₂ O ₃ : 20.5 38 Y ₂ O ₃ : 19 Y ₂ O ₃ : 9.5 Al ₂ O ₃ : 51 Al ₂ O ₃ : 25.5 ZrO ₂ : 17.9 ZrO ₂ : 8.95 La ₂ O ₃ : 12.1 La ₂ O ₃ : 6.05 ^* For this example, use the same grinding methodology as in example 36

Table 4 Raw material Source Particles of alumina (Al ₂ About ₃ ) Obtained from Condea Vista, Tucson, pc. Arizona, under the trade designation "ARA-0.5" Gadolinium oxide particles (Gd ₂ O ₃ ) Obtained from Molycorp Inc., Mountain Pass, pc. California Lanthanum oxide particles (La ₂ O ₃ ) Obtained from Molycorp Inc., Mountain Pass, pc. California Yttrium stabilized zirconia particles (Y-PSZ) Obtained from Zirconia Sales, Inc. of Marietta. Georgia, under the trade name "HSY-3" Yttrium oxide particles (Y ₂ O ₃ ) Received from N.C. Stark Newton, pc. Massachusetts

The various properties / characteristics of some materials of examples 36-39 are determined as follows. X-ray powder diffraction (using an X-ray diffractometer (obtained under the trade name "PHIL-LIPS XRG 3100" from PHILLIPS, Machwah, NJ) with Kα1 radiation of copper 1.54050 Angstrom) is used to qualitatively determine the phases present in the materials of the example. ) The presence of a wide diffuse intensity peak is taken as an indication of the amorphous nature of the material. The existence of both a broad peak and well resolved peaks takes as an indication of the existence of a crystalline material in an amorphous matrix. The phases defined in the various examples are shown in Table 5 below.

Table 5 Example X-ray diffraction detected phases Color T _g, ° C T _x , ° C Pace. hot pressing, ° C 36 Amorphous ^* Transparent 840 925 960 37 Amorphous ^* Transparent 886 933 985 38 Amorphous ^* Transparent 843 938 970 ^* Glass, since the material of the example has T _g

For differential thermal analysis (DTA), the material is sieved to select balls with sizes ranging from 90-125 micrometers. DTA data is obtained (using a device obtained from Netzsch Instruments, Selb, Germany, under the trade designation "NETZSCH STA 409 DTA / TGA"). The amount of each sieved sample placed in a 100 μl Al ₂ O ₃ sample holder is 400 milligrams. Each sample is heated in static air at a speed of 10 ° C / min from room temperature (approximately 25 ° C) to 1200 ° C.

For each of Examples 36-38, approximately 25 grams of balls were placed in a graphite mold and hot stamped using a single screw press device (obtained under the trade name "HP-50", Thermal Technology Inc., Brie, Calif.). Hot stamping is carried out in an argon atmosphere at a pressure of 13.8 megapascals (MPa) (2000 pounds per square inch). The hot pressing temperature at which a noticeable glass flow occurs, which is shown by the control unit for the extrusion of the hot pressing equipment described above, is shown for various examples in Table 5. About 400 grams of balls of Example 36 and 200 grams of balls of Example 37 are hot pressed.

The balls of examples 36-38 are thermally treated in an oven (an electric heating furnace (obtained under the trademark "Model KKSK-666-3100" from Keith Furnaces Pico Rivera, Calif.) As follows. The balls are heated from room temperature (approximately 25 ° C) to about 1300 ° C at a speed of about 10 ° C / min and then kept at 1300 ° C for about 1 hour before cooling to room temperature by turning off the oven.

13 and 14 are micrographs from a scanning electron microscope (SEM) of a polished section of the heat-treated materials of Examples 36 and 37, respectively. Polished sections are prepared using traditional installation and polishing techniques. Polishing is carried out using polishing material (obtained from Buehler, Lake Bluff, Illinois under the trade name "ECOMET 3 TYPE POLISHER-GRINDER"). The sample is polished for 3 minutes with a diamond cutting wheel, followed by polishing for three minutes with each of 45, 30, 15, 9 and 3 micrometer diamond suspensions. The polished sample was coated with a thin layer of gold-palladium and observed using JEOL SEM (Model JSM 840A).

The phases present after the heat treatment are analyzed using x-ray diffraction techniques as described above. The results are summarized in Table 6 below.

Table 6 Example X-ray diffraction detected phases Hardness, GPa 35 Cubic / tetragonal ZrO ₂ 16.4 ± 0.3 α-Al ₂ O ₃ LaAl ₁₁ O ₁₈ LaAlO ₃ 36 LaAl ₁₁ O ₁₈ 16.0 ± 0.4 LaAlO ₃ 37 Cubic / tetragonal ZrO ₂ 16.9 ± 0.1 GdAlO ₃ α-Al ₂ O ₃ 38 Cubic / tetragonal ZrO ₂ Y ₃ Al ₅ O ₁₂ LaAlO ₃ α-Al ₂ About ₃

The average microhardness of the heat-treated beads from the selected Examples 35-38 was measured by setting loose beads (approximately 125 micrometers in size) in a base resin (obtained under the trade designation "EROMET 3" from Buehler Ltd., Lake Bluff, Illinois). The resulting resin cylinder is approximately 2.5 cm (1 inch) in diameter and approximately 1.9 cm (0.75 inch) in height. Installed samples are polished using a conventional crushing / polishing device (obtained under the trade name "EROMET 3" from Buehler Ltd.) and conventional diamond suspensions using a 1-micrometer diamond suspension at the last stage of polishing (obtained under the trade name "METADI" from Buehler Ltd.) to obtain polished cross sections of the sample.

Microhardness measurements are carried out using a conventional microhardness meter (obtained under the trade name "MITUOTO MVK-VL" from Mitutoyo Corporation, Tokyo, Japan) equipped with a Vickers indenter using a 500 gram tip load. Microhardness measurements are carried out in accordance with the instructions set forth in ASTM Test Method E384 Test Methods for Microhardness of Materials (1991). Microhardness values are average for 20 measurements. The average values of microhardness are presented above in Table 6.

Grinding Efficiency for Examples 35, 35A and 36 and Comparative Examples D-F

The hot pressed material of Examples 35 and 36 is crushed using a Chipmunk jaw crusher (Type VD, manufactured by BICO Inc., Burbank, Calif.) To (abrasive) particles and sorted to collect fractions of -25 + 30 mesh (i.e. fractions collected between sieves with openings of 25 and 30 micrometers) and fractions -30 + 35 mesh (i.e. fractions collected between sieves with openings of 30 and 35 micrometers) (standard US test sieves) . These two mesh fractions are combined to form a 50/50 mixture. The mixed material is thermally treated at 1300 ° C for 1 hour, as described above. Thirty grams of the obtained glass-ceramic abrasive particles are introduced into the coated abrasive wheel. A coated abrasive wheel is prepared in accordance with conventional techniques. Glass ceramic abrasive particles are bonded to vulcanized fiber substrates with a diameter of 17.8 cm and a thickness of 0.8 mm (having a central hole of 2.2 cm in diameter) using a conventional phenol-forming phenol-forming polymer (48% resol-phenolic polymer, 52% calcium carbonate, diluted to a solids content of 81% with water and glycol ether) and a conventional phenol adhesive polymer filled with cryolite (32% resol-phenolic polymer, 2% iron oxide, 66% cryolite, diluted to a solids content of 78% in oh and glycol ether). The mass of the wet forming polymer is approximately 185 g / m ² . Immediately after applying the forming coating, the glass-ceramic abrasive particles are electrostatically coated. The forming polymer is pre-cured for 120 minutes at 88 ° C. Next, a phenolic adhesive coating filled with cryolite is applied to the forming coating and abrasive particles. The wet glue mass is approximately 850 grams per square meter (g / m ² ). The adhesive polymer is cured for 12 hours at 99 ° C. Coated abrasive wheels are bent before testing.

The coated abrasive wheel of Example 35A is prepared as in Example 36, except that the abrasive particles of Example 35A are more often obtained by crushing the material of Example 35 after hot pressing and heat treatment than by crushing the material after the heat treatment.

Coated abrasive wheels of Comparative Example D were prepared as described for Example 35, except that heat-treated fused alumina abrasive particles (obtained under the trade name "ALODUR BFRPL" from Triebacher, Villach, Austria) were used instead of the glass-ceramic abrasive particles of Example 35.

Coated abrasive wheels of Comparative Example E were prepared as described for Example 35, except that the abrasive particles of alumina-zirconia (having a eutectic composition of 53% Al ₂ O ₃ and 47% ZrO ₂ ; obtained under the trade name "NORZON" from Norton Company, Worcester, Mass.) is used instead of the glass ceramic abrasive particles of Example 35.

Coated abrasive wheels of comparative example F receive, as described for example 35, except that the abrasive particles obtained by sol-gel technology (marketed under the trade name "321 CUBITRON" from 3M Company, St. Paul, Minnesota ), used instead of glass-ceramic abrasive particles of example 35.

The grinding efficiency of coated abrasive wheels of examples 35, 35A, 36 and comparative examples D-F is evaluated as follows. Each coated abrasive wheel is mounted on an inclined aluminum support and used to grind the front surface of a pre-weighed mild steel workpiece 1018 1.25 cm × 18 cm × 10 cm. The wheel is rotated at 5000 rpm, while the part of the wheel placed on an inclined aluminum support, in contact with the workpiece at a load equal to 8.6 kilograms. Each wheel is used to grind an individual workpiece in succession at intervals of one minute. The total slice represents the total amount of material removed from the workpiece during the testing period. The total cut for each sample after 12 minutes of grinding, as well as the cut at 12 minutes (i.e. the final cut) are shown below in Table 7. The results of examples 35 and 36 are average results for two circles, while for each of examples 35A and comparative examples D, E and F test one circle.

Table 7 Example The total cut, g The final cut, g 35 1163 91 35A 1197 92 36 1094 91 Comp. D 514 28 Comp. E 689 53 Comp. F 1067 89

It will be apparent to those skilled in the art that various modifications and variations of the present invention can be made without departing from the scope and spirit of the present invention and that the illustrative embodiments of the invention provided herein do not in any way limit the present invention.

Claims (24)

1. Glass ceramics with an average hardness of at least 13 GPa, having x, y and z dimensions perpendicular to each other, each of the dimensions of x, y and z being at least 5 mm. 2. Glass ceramic according to claim 1, the hardness of which is at least 15 GPa. 3. Glass ceramic according to claim 1, the hardness of which is at least 16 GPa. 4. Glass ceramic according to claim 3, the hardness of which is at least 17 GPa. 5. Glass ceramic according to claim 4, the hardness of which is at least 18 GPa. 6. Glass ceramic according to claim 1, containing at least 35 wt.% Al ₂ O ₃ relative to the total weight of glass ceramic. 7. Glass ceramic according to claim 1, containing a total of not more than 10 wt.% As ₂ O ₃ , B ₂ O ₃ , GeO ₂ , P ₂ O ₅ , SiO ₂ , TeO ₂ and V ₂ O ₅ relative to the total weight of glass. 8. Balls containing glass ceramics according to claim 1. 9. A set of abrasive particles with a specific nominal discharge, having at least part of the set of abrasive particles containing glass ceramics with an average value of hardness of at least 15 GPa. 10. The set of abrasive particles according to claim 9, in which the hardness of the glass ceramic is at least 16 GPa. 11. The set of abrasive particles of claim 10, in which the hardness of the glass ceramics is at least 18 GPa. 12. The set of abrasive particles according to claim 9, in which a specific nominal discharge is selected from the group of bits ANSI, including ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI 24, ANSI 36, ANSI 40, ANSI 50, ANSI 60, ANSI 80, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI 240, ANSI 280, ANSI 320, ANSI 360, ANSI 400 and ANSI 600. 13. The set of abrasive particles according to claim 9, in which a specific nominal discharge is selected from the group of discharges FEPA, including P8, P12, P16, P24, P36, P40, P50, P60, P80, P100, P120, P150, P180, P220, P320, P400, P500, P600, P800, P1000 and P1200. 14. The set of abrasive particles according to claim 9, in which a specific nominal discharge is selected from the group of discharges JIS, including JIS8, JIS12, JIS16, JIS24, JIS36, JIS46, JIS54, JIS60, JIS80, JIS100, JIS150, JIS180, JIS220, JIS240, JIS280, JIS320, JIS360, JIS400, JIS600, JIS800, JIS1000, JIS1500, JIS2500, JIS4000, JIS6000, JIS8000 and JIS 10000. 15. An abrasive article comprising a binder and a combination of abrasive particles, wherein at least a portion of the combination of abrasive particles comprises glass ceramics with an average hardness of at least 15 GPa. 16. The abrasive product according to clause 15, which is an abrasive product with a binder, an abrasive product on a nonwoven basis or an abrasive product with a coating. 17. A method of grinding a surface, comprising using an abrasive article comprising a binder and a combination of abrasive particles, wherein at least a portion of the abrasive particles comprises glass ceramics with an average hardness of at least 15 GPa; bringing into contact at least one of the abrasive particles containing glass ceramics with the surface of the workpiece; the movement of at least one of the contacted abrasive particles containing glass ceramics, or the contact surface, resulting in grinding of at least part of the surface with an abrasive particle containing glass ceramics and in contact with this surface. 18. A method for producing glass ceramics, including heat treatment of an amorphous material, as a result of which at least a portion of the amorphous material is converted to glass ceramics having an average hardness of at least 13 GPa, and x, y and z measurements perpendicular to each other, each of the measurement dimensions x, y and z is at least 5 mm, while the amorphous material contains at least 35 wt.% Al ₂ O ₃ relative to the total weight of the amorphous material, and a metal oxide other than Al ₂ O ₃ , and also contains in general minutes of not more than 10 wt.% As ₂ O _3, B ₂ O _3, GeO _2, P ₂ O _5, SiO _2, TeO _2, and V ₂ O ₅ with respect to the total weight of the amorphous material. 19. A method of producing a glass-ceramic product, comprising obtaining glass particles, which has a glass transition temperature T _g and contains at least 35 wt.% Al ₂ O ₃ with respect to the total weight of glass in each particle, and a metal oxide other than Al ₂ O ₃ , and also contains a total of not more than 10 wt.% As ₂ O ₃ , B ₂ O ₃ , GeO ₂ , P ₂ O ₅ , SiO ₂ , TeO ₂ and V ₂ O ₅ with respect to the total mass of glass in each particle; heating the glass particles to a temperature exceeding T _g so that as a result the glass particles coalesce to form a specific shape; cooling the mold to form a glass product; heat treatment of the glass product, as a result of which at least a portion of the glass is converted into glass ceramics to produce a glass ceramic product, the glass ceramics having an average hardness value of at least 13 GPa. 20. A method for producing abrasive particles, comprising heat treating particles containing an amorphous material, as a result of which at least a portion of the amorphous material is converted to glass ceramics to produce abrasive particles containing glass ceramic, having an average hardness of at least 15 GPa, and amorphous the material in each particle contains at least 35 wt.% Al ₂ O ₃ with respect to the total mass of amorphous material in each particle, and a metal oxide other than Al ₂ O ₃ , and also contains a total complexity not more than 10 wt.% As ₂ O ₃ , B ₂ O ₃ , GeO ₂ , P ₂ O ₅ , SiO ₂ , TeO ₂ and V ₂ O ₅ with respect to the total mass of amorphous material in each particle. 21. The method according to claim 20, in which before the heat treatment of particles containing amorphous material, receive a set of particles with a specific nominal discharge, and at least part of the particles is a collection of particles of glass, and heat treatment is carried out so as to result in a set abrasive particles with a specific nominal discharge and at least a portion of abrasive particles containing glass ceramics. 22. The method according to claim 20, which further includes sorting the abrasive particles containing glass ceramics, to obtain a population of abrasive particles with a specific nominal discharge and at least part of the population of abrasive particles containing glass ceramic. 23. A method of producing abrasive particles, comprising heat treatment of an amorphous material, as a result of which at least a portion of the amorphous material is converted to glass ceramics having an average hardness of at least 15 GPa, the amorphous material containing at least 35 wt.% Al ₂ O ₃ with respect to the total mass of the amorphous material and a metal oxide other than Al ₂ O ₃ , and also contains a total of not more than 10 wt.% As ₂ O ₃ , B ₂ O ₃ , GeO ₂ , P ₂ O ₅ , SiO ₂ , TeO ₂ and V ₂ O ₅ with respect to the total mass of the amorphous material; crushing of glass ceramics to obtain abrasive particles containing glass ceramics. 24. A method of producing glass ceramics, comprising combining at least (a) glass, characterized by a glass transition temperature T _g and containing at least 35 wt.% Al ₂ O ₃ relative to the total weight of the glass, and at least one metal oxide, excellent from Al ₂ O ₃ , as well as containing a total of not more than 10 wt.% As ₂ O ₃ , B ₂ O ₃ , GeO ₂ , P ₂ O ₅ , SiO ₂ , TeO ₂ and V ₂ O ₅ relative to the total weight of glass; (b) heat resistant particles compared to glass particles; heating the glass particles to a temperature exceeding T _g so that as a result the glass particles coalesce; glass cooling to obtain ceramics; heat treatment of ceramic glass, as a result of which at least part of the glass is converted into glass ceramics, which has an average value of hardness of at least 13 GPa.

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