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WO2006014187A2 - Procedes d'utilisation de corps broyants polycarbure - Google Patents

Procedes d'utilisation de corps broyants polycarbure Download PDF

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Publication number
WO2006014187A2
WO2006014187A2 PCT/US2005/007744 US2005007744W WO2006014187A2 WO 2006014187 A2 WO2006014187 A2 WO 2006014187A2 US 2005007744 W US2005007744 W US 2005007744W WO 2006014187 A2 WO2006014187 A2 WO 2006014187A2
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WIPO (PCT)
Prior art keywords
particles
feed particles
carbide
metal
titanium
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Ceased
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PCT/US2005/007744
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WO2006014187A3 (fr
Inventor
Robert Dobbs
Leonard E. Dolhert
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Primet Precision Materials Inc
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Primet Precision Materials Inc
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Filing date
Publication date
Priority claimed from US10/797,343 external-priority patent/US7140567B1/en
Application filed by Primet Precision Materials Inc filed Critical Primet Precision Materials Inc
Publication of WO2006014187A2 publication Critical patent/WO2006014187A2/fr
Publication of WO2006014187A3 publication Critical patent/WO2006014187A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B01J37/0027—Powdering
    • B01J37/0036—Grinding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00—Materials not provided for elsewhere
    • C09K3/14—Anti-slip materials; Abrasives
    • C09K3/1409—Abrasive particles per se

Definitions

  • This invention relates generally to the field of multi-carbide materials, and more specifically to the use of grinding media formed of multi-carbide materials in the shape of spheres or other shaped media to produce very small particles, and to the use of those very small particles produced using the multi-carbide grinding media.
  • Carbide materials are well known in the art of material science. They include a range of compounds composed of carbon and one or more carbide- forming elements such as chromium, hafnium, molybdenum, niobium, rhenium, tantalum, thallium, titanium, tungsten, vanadium, zirconium, and others. Carbides are known for their extreme hardness with high temperature tolerance, properties rendering them well-suited for applications as cutting tools, drilling bits, and similar uses. Multi-element carbides are known for their improved toughness and hardness relative to single element carbides. Single element carbides are typically used with a metal binder to impart toughness.
  • Multi-carbides are formed by combining two or more carbide- forming elements with carbon. Some multi-carbides have other non-carbide forming elements in the composition, such as nitrogen, but are here referred to simply as multi-carbides since the dominant components are carbide-forming elements. For example, a combination of tungsten and titanium with carbon and nitrogen would be such a multi-carbide material.
  • Some multi-carbide compositions are formed with a deficiency of carbon resulting in some small percentage of carbide-forming element not being converted to a carbide and instead remaining as uncombined elemental metal. These combinations can enhance certain of the favorable qualities of carbides, with some combinations increasing hardness, others increasing toughness, and so forth. Very small variations in composition can greatly affect the material's properties. Many of these variations are well understood by practitioners of the art and are amply published.
  • a primary manufacturing method used to manufacture carbides is to place the elements to be fused on the recessed surface of a large electrode. A very high current is passed from that electrode through the material and into another electrode in proximity, subjecting the material to the heat of an electric arc. This process is effective in fusing the materials, but causes inconsistent mixing of the elements in the compound and some uncontrolled loss of material due to vaporization, phenomena that can greatly compromise the properties of the resulting compound in uncontrolled and unpredictable ways. Hardness is also a challenge, as the manufacturing process results in an irregularly-shaped lump of resulting compound that is generally a few inches in diameter, colorfully known as a "cow chip".
  • the "chip” is very hard, and is worked into smaller shapes only by percussive shocking or other crushing method that cleaves the chip into useful sizes. These processes leave small cracks in the finished product that greatly reduce both its hardness and its mechanical toughness. Re-melting of the material after crushing imposes high cost, and cannot efficiently achieve regular particle sizes or shapes. Consequently, although carbide is available in small spheres and other preferred shapes, those spheres are not optimally composed, they are irregularly sized, they are expensive, and they are lacking in effectiveness. [07] The known art currently does not have a process whereby multi-carbide materials can be formed into small and regular shapes without loss of optimized properties due to process variation in manufacture or degradation of material during shaping.
  • grinding media spheres, rods or more irregular objects
  • product material material to be reduced
  • grinding media range greatly in size, from ore crushers that are several inches in diameter, down to micron- sized particles that are themselves used to mill much smaller particles. Grinding media also vary greatly in shape, including spherical, semi-spherical, oblate spherical, cylindrical, diagonal, rods, and other shapes (hereinafter "shaped media"), and irregular natural shapes such as grains of sand.
  • Grinding media are used in various devices such ball mills, rod mills, attritor mills, stirred media mills, pebble mills, etc. Regardless of their differences in design, all mills operate by distributing product material around the grinding media and by causing collisions to occur between grinding media units such that product material particles are positioned between the colliding grinding media units. These collisions cause fracturing of product material particles into to smaller dimensions, an effect known descriptively as "size reduction” or “comminution.” [012] The materials used as grinding media also are frequently used as applied abrasives.
  • such materials are aggregated in molds and held together by a binder such as molten metal that is poured into the mold and cooled, rendering a "hard body” that is impregnated by the binder material.
  • Hard body materials also known as “hard bodies”
  • Similar processes are used to impregnate the materials in grinding discs and wheels.
  • Various adhesives are used to bind the materials to textiles, papers and other strata for use as sandpapers, sanding belts, and similar products.
  • Hardness of the grinding medium determines milling effectiveness
  • mass density determines milling efficiency
  • mechanical toughness determines product purity and overall process efficiency.
  • Hard materials transfer energy efficiently in collisions with product material for effective milling
  • high-density materials increase the energy transfer per collision with product material and thus increase milling efficiency, especially for small-dimension grinding media
  • tough materials can be used for longer periods before they fail and contaminate the product material or otherwise require replacement.
  • An ideal milling material is thus very hard, of very high mass density, and very tough.
  • those qualities will hold as the size of the grinding media is reduced, and regardless of the chosen shape of the grinding media.
  • the history of engineering materials for grinding media is a history of accepting tradeoffs among these material properties, as improvement in one of these factors has previously produced an offsetting reduction in one or more of the others.
  • yttria-stabilized zirconia shows good mechanical toughness, but with low mass density.
  • Various metal media have relatively high mass density, but low mechanical toughness.
  • Carbides showed extreme hardness and mass density, even in small dimensions, but with unavoidable media failures that cause unacceptable product contamination and more general process failures that are incompatible with many applications.
  • U.S. Patent No. 5,407,564 (Kaliski) is illustrative. Kaliski discloses a range of high mass density, single-element carbides selected from tungsten, thallium, niobium, and vanadium in sizes ranging between 10 and 100 microns with a requirement of high theoretical density. As Kaliski explains, high theoretical density, nonporous materials are needed. These materials showed impressive results in producing fine and regular product material in small quantities under controlled laboratory conditions. Duplication of his example showed his invention to cause contamination of the milled product, as longer- term and higher- volume production attempts failed due to lack of mechanical toughness that caused metallic and other contamination of product material.
  • High density ceramics without metal binders such as tungsten carbide combined with tungsten di-carbide
  • Kaliski specifically recommends choosing among his claimed materials to select those whose contaminants provide the most good, or at least do the least damage, to the milled product. These materials changed the nature of but did not resolve the product material contaminant issue, and did not solve the mechanical toughness problem. Rather, these materials tended to fail by degradation into hard, fine and irregular shards that acted as abrasives in the media mill, contaminating the product and on one occasion seriously damaging the mill itself.
  • U.S. Patent No. 5,704,556 discloses ceramic grinding media without metal binders in dimensions of less than 100 microns diameter. While these materials are acceptably hard, and show greater mechanical toughness than those disclosed in Kaliski, they lack adequate density for many applications or for optimum efficiency in others.
  • the inventor of the present invention made an effort to make suitable grinding media from available spherical carbides, of which only single element carbides are known in the art.
  • Tungsten carbide/tungsten di-carbide spheres were purchased in conformance to Kaliski's specification and used in a shaker mill, but comminution to the degree cited by Kaliski was not evident.
  • Plasma-processed spherical tungsten carbide/tungsten di-carbide was also purchased from another source, in conformance to Kaliski's specification, in sufficient quantity to test on a production scale. This grinding media fractured due to insufficient mechanical toughness, contaminating the product and extensively damaging the media mill.
  • U.S. Patent No. 2,581,414 (Hochberg), U.S. Patent No. 5,478,705 (Czekai), and U.S. Patent No. 5,518,187 (Bruno) disclose polymer grinding media which show high mechanical toughness and cause relatively benign product material contamination upon grinding media failure. However, they show low hardness and density relative to ceramics. Polymer grinding media thus can be useful in milling relatively soft product materials that are sensitive to product contamination, and in industries that are relatively insensitive to processing cost, such as in drug processing or in dispersing biological cells for analysis, but they are not appropriate for the majority of industrial applications.
  • U.S. Patent Nos. 3,690,962, 3,737,289, 3,779,745, and 4,066,451 disclose certain multi-carbides for use as cutting tools. Although the multi-carbides disclosed showed a combination of hardness, density and mechanical toughness that promised to be useful for milling, the known geometries for available multi-carbide materials rendered them incompatible with such use. Difficulties included the large size of multi-carbide material that is produced by current manufacturing methods, and difficulty in machining or otherwise manipulating the material into sizes and shapes useful for milling due in part to its hardness and mechanical toughness.
  • fine particles of a predetermined size between 1 x 10 ⁇ 9 meters and 20 microns are produced from larger feed particles of the material by processing the feed particles in a media mill, where the media are particles of multi -carbide.
  • the multi- carbide has a mass density greater than 8 gm/cc and a hardness and toughness sufficient not to introduce contamination of the processed feed particles to a maximum degree greater than about 100 to about 900 ppm.
  • the processing is at an energy intensity to cause size reduction of the feed particles for a period of time effective to reduce the particle size to the predetermined size.
  • Other materials can also be processed using the spheres to obtain particle sizes down to 1 x 10 "9 meters.
  • a method for producing fine particles of a material from larger feed particles of the material includes the step of processing the feed particles in a media mill using media of multi-carbide with a mass density greater than 8 gm/cc and a hardness and toughness sufficient so as not to introduce contamination of resulting milled particles to an extent greater than a maximum degree of contamination; the processing being at an energy intensity to cause size reduction of the feed particles, in the media mill, for a period of time sufficient to reduce a particle size to a predetermined size.
  • a method for producing fine particles of a material from larger feed particles of the material includes the step of processing the feed particles in a media mill using media of multi-carbide wherein the multi-carbide comprises carbon and at least two different carbide-forming elements; the processing being at an energy intensity to cause size reduction of the feed particles, in the media mill, for a period of time sufficient to reduce a particle size to a predetermined size, wherein the step of processing does not introduce contamination of resulting milled particles to an extent greater than a maximum degree of contamination.
  • a method for producing fine particles of a material from larger feed particles of the material includes the step of processing the feed particles in a media mill using spherical media of multi-carbide wherein the multi-carbide comprises carbon and one carbide-forming element selected from the group consisting of chromium, hafnium, molybdenum, niobium, rhenium, tantalum, thallium, titanium, tungsten, vanadium, and zirconium, along with the elemental metal of the carbide- forming element; the processing being at an energy intensity to cause size reduction of the feed particles, in the media mill, for a period of time sufficient to reduce a particle size to a predetermined size, wherein the step of processing does not introduce contamination of resulting milled particles to an extent greater than a maximum degree of contamination.
  • Fig. 1 shows particles produced according to the prior art.
  • Fig. 2 shows particles produced according to an embodiment of the present invention.
  • a compound is formed from a combination of carbon and two or more different carbide- forming elements ("multi-carbide” or “multi-carbide material", defined more fully below).
  • Multi-carbide materials have extreme hardness, extreme density, and extreme mechanical toughness.
  • the selection of carbide- forming elements of the multi-carbide materials, and the precise proportional composition for any combination of those elements, is modified to alter the properties of the material.
  • multi-carbide material is combined with one or more elemental metals of the chosen carbide to alter ductility and other properties of the material. Multi-carbide material is formed effectively and efficiently into a variety of shaped media, preferably into spheres, by the use of novel manufacturing methods.
  • the manufacturing method of the present invention maintains proper element composition to optimize desired material properties, produces useful shaped media, avoids crushing or other degradation of the material to create the shaped media, and greatly lowers manufacturing cost to produce shaped media formed from such material while improving the quality of the material obtained.
  • the manufacturing method produces small and regular spheres of optimized multi-carbide material that is suitable for use as grinding media in media mills ("multi-carbide grinding media").
  • the multi- carbide grinding media of the present invention are used in shaped media ranging in size from 100 mm or more down to 0.5 microns or less while maintaining their effective material properties.
  • the multi-carbide grinding media are used in media mills and other extant milling processes of varying design and capacity. By such use of such multi- carbide grinding media, greater product material size reduction, size regulation, and purity can be achieved than by utilization of extant milling media materials.
  • the multi-carbide grinding media of the present invention are used effectively in a variety of applications other than media mills, such as the manufacture of hard bodies, grinding wheels, abrasive papers and textiles, cladding materials, and hard coating materials.
  • the invention permits the manufacture of materials in dimensions and purities that previously were unattainable ("ultra-fine particles"). Ultra-fine particles will enable the manufacture of products previously unattainable, or attainable only by less effective or more expensive methods. Examples include sub-micron sized oxides, such as oxides of titanium. Reduction of certain oxides of titania with sufficiently low impurities causes that compound to exhibit special properties including high transparency. Fine size reduction of pigments improve the efficiency of color distribution in dyes and paints. Similar results are obtained by high refinement of varnishes and other finishes.
  • Ultra-fine particles of certain metals and other materials will permit the manufacture of those materials at previously-unachieved economic or performance properties and in superalloy and other combinations not previously obtainable.
  • Diamond particles can be reduced to dimensions not previously obtainable due to their hardness relative to known grinding media, permitting more efficient use of diamond particles at reduced cost.
  • Ultra-fine particles will become available that can be formed by molding, electrostatic deposition and other known methods into microelectromechanical products and other micron-scale devices that previously were obtainable only by etching of glass or silicon or other semiconductors. Ultra- fine particles can be introduced to certain liquids to form fluids that exhibit special properties of heat transmission, solubility and other qualities.
  • the invention also permits the manufacture of ultra- fine particles with geometries superior to those achieved by known manufacturing methods.
  • chemical precipitation can create particles of certain materials in extremely small dimensions. Those particles, however, generally exhibit smooth and rounded shapes.
  • Fig. 1 shows particles that were assembled atomistically by precipitation. Such particles are also typical of those particles produced by known means such as sol gel, vapor phase condensation, etc.
  • the science dealing with the surface topography of particles speaks in terms of a fractured surface which has discernible cleavage facets and cleavage steps. These two features are specifically absent from the particles produced by the known processing methods for producing very small particles.
  • Another missing feature in particles produced according to prior art methods is concavity. Concavity is defined as that condition where some portion of the surface lies beneath the surrounding surface. In precipitated particles, the surface is bulbulous, meaning that a portion of the surface protrudes above the surrounding surface such as is always true in the case of a sphere.
  • ultra-fine particles produced by milling according to the present invention exhibit more angular geometries with cleaved surfaces and angular intersecting surfaces that exhibit higher activity relative to the materials formed by other means, causing ultra-fine milled particles to tend to exhibit superior chemical and mechanical properties over particles of similar size and dimension that are manufactured by precipitation and similar methods. Note the corners, flat edges, etc. of the very small particles produced by the milling method of the present invention.
  • a catalyst produced according to the present invention is less than 3O x 10 '9 meters in all dimensions and possesses cleaved surfaces, the catalyst being uniquely distinguishable by its particle surface features having a preponderance of cleavage facets and/or cleavage steps, the catalyst alternatively being uniquely distinguishable by the acutance of a preponderance of intersecting surfaces in which the arc length of the edge is less than the radius of the edge, the catalyst alternatively being uniquely distinguishable by surface concavities greater than 5% of the particle diameter, the catalyst alternatively being uniquely distinguishable by the acutance of a preponderance of intersecting surfaces in which the included angle of the edge radius is about, or less than, the included angle of the intersecting surfaces.
  • Intermetallic particles produced according to the present invention have less than 30 x 10 "9 meters in all dimensions and possess cleaved surfaces.
  • the product is uniquely distinguishable by its particle surface features having a preponderance of cleavage facets and/or cleavage steps, the product alternatively being uniquely distinguishable by the acutance of a preponderance of intersecting surfaces in which the arc length of the edge is less than the radius of the edge, the catalyst alternatively being uniquely distinguishable by surface concavities greater than 5% of the particle diameter, the product alternatively being uniquely distinguishable by the acutance of a preponderance of intersecting surfaces in which the included angle of the edge radius is about, or less than, the included angle of the intersecting surfaces.
  • the grinding media of the present invention are also useful in other fields. Examples include the manufacture of "hard bodies" for drilling or grinding, laser cladding and other cladding processes, use as surface materials, and other applications. For instance, grinding media are used without media mills as a component of alloys to be applied to surfaces for improved wear resistance. Two common methods of applying such protective coatings are known as cladding and surfacing. Each of these have many methods employed, the choice of which depending on the object and alloy to be treated. Generically, binder materials such as polymers or metals are used to hold grinding media onto the surface of the object being treated by cladding or surfacing. The binder materials are melted or cast into place along with the grinding media material which itself is not melted during the cladding or surfacing operation.
  • Typical melting methods include laser, furnace melting, welding tubes and plasma heat sources.
  • the binder material itself often cannot withstand the wear imposed on the surface by the operating environment such as in oil well drilling. This binder wear exposes the grinding media to the surface, thereby providing a wear resisting surface protection. These same surfaces are often exposed to very high shock impacts which the grinding media is able to withstand.
  • multi-carbide material a compound formed from carbon and at least two carbide-forming elements.
  • U.S. Patent Nos. 3,690,962, 3,737,289, 3,779,745, and 4,066,451 (all to Rudy), incorporated herein by reference, disclose how to make such multi-carbide materials for use as cutting tools.
  • the multi-carbide material is formed from carbon and carbide-forming elements selected from the group consisting of chromium, hafnium, molybdenum, niobium, rhenium, tantalum, thallium, titanium, tungsten, vanadium, zirconium, and any other carbide forming element.
  • Multi-carbide material can be formed either with or without some of the carbide-forming elements not being fully carburized and thus remaining in the material in its elemental state.
  • the multi-carbide material can contain a certain amount of impurities and other extraneous elements without significantly affecting its material properties.
  • the production of spheres from irregular shaped particles can be achieved by various means.
  • One common method of processing ultrahigh melting point materials into spheres is with the use of a thermal plasma torch. Such a torch can operate at temperatures well beyond the melting point of all multi-carbide materials.
  • Other methods, such as melt atomization or arc melting, are known to those familiar with the art and there is no intention to limit the practice to just the use of these named methods. In short, any known technique for applying heat which brings the material to its melting point will work. How to form other shaped media is also known in the art.
  • the known methods of forming spheres from carbides also form spheres when the known methods are applied to multi-carbide materials, but the acceptable spheres amount to approximately 40 % of the total produced.
  • a new method for producing spheres from multi-carbide materials was therefore developed. According to an embodiment of the invention, the method for producing spheres from multi-carbide materials is as follows.
  • the multi-carbide material is formed into spheres preferably by admixing fine particles of the elements intended to comprise the multi-carbide material in appropriate ratios, by adequately mixing the components, by maintaining the stability of the mixture by introduction of an inert binding agent, by subdividing the mixture into aggregates each having a mass approximately equal to that of the desired sphere to be formed, by applying heat to the subdivided aggregate sufficient to cause its elements to fuse, and by cooling the fused sphere in a manner that preserves its spherical shape.
  • This manufacturing process is used to make small and regular spheres that are composed of multi-carbide material. Spheres of very small diameters, i.e., less than 500 microns diameter and down to 0.5 microns diameter, with regular geometries and predictable, optimized compositions can be produced.
  • Spheres of multi-carbide material can be formed in this manner by the use of a thermal plasma torch or vertical thermal tube to raise the temperature of the multi-carbide particles above their melting point as they pass through the plasma or down the tube.
  • Such spheres can be utilized as grinding media in media mills ("multi-carbide grinding media"), as the grinding medium in a hard body drill bit or grinding wheel, as the abrasive medium for "sand blasting" shaping techniques, and in other applications.
  • Multi-carbide grinding media media mills
  • a variety of shapes can be formed by molding and sintering sufficiently small particles of the multi-carbide material. The geometry of such shapes can be varied nearly arbitrarily to achieve different grinding properties.
  • the manufacturing process is an improvement over the current art in that it forms multi-carbides by processes that better mix and do not vaporize elements during manufacture, improving predictability and performance characteristics of the produced material; and that do not crack or otherwise degrade the material as it is formed into useful shapes, to improve the mechanical toughness of the produced material.
  • the multi-carbide grinding media of whatever shape, can be used in media mills to achieve efficient and thorough comminution of materials with high purity due to the extreme hardness, extreme density, and extreme mechanical toughness of the material, independent of size or shape, hi such applications, particles of product material to be reduced in size are admixed with the colliding grinding media.
  • the product material particles, interspersed between the grinding media units, are rapidly reduced in size. Reductions to controlled dimensions as small as 10 "9 meters can be achieved and readily reproduced with the right combination of initial source material, grinding media and media mill or other reduction process.
  • the wear rates of the grinding media units are extremely low and their grinding effectiveness is very high, enabling the efficient conversion of coarse particles into extremely small product size while maintaining high purity. That is, the multi-carbide grinding media deliver virtually no contamination to the product material.
  • the media of the present invention include mill media of any geometry composed of multiple carbide-forming elements, with carbon, having a density greater than 8 gm/cc and a combination of hardness and toughness sufficient to permit use in a media mill without contamination of the milled product to an amount greater than 800 ppm.
  • a method for making spheres, composed of multiple carbide- forming elements, with carbon, for use as mill media, or in cladding material, as surfacing material, or in hard body materials containing these spheres includes the steps of:
  • a method for producing fine oxides of any metal but in particular titanium, being of a size less than 3 microns and including down to 1 x 10 "9 using larger particles of oxides of titanium includes the steps of:
  • feed oxides (a) obtaining large particles of oxides, especially of titanium, because such oxide particles are typically much cheaper to procure than fine particles of oxides of titanium, hereinafter such particles being termed feed oxides;
  • a method for producing highly transparent oxides of titanium includes the steps of:
  • a method for producing titanium metal includes the steps of:
  • the present invention can be used for producing diamond particles of less than about 100 x 10 "9 meters in all dimensions and, if desired, of a tight particle size distribution, with the diamond particles being usable for CMP (chemical mechanical polishing) and other polishing applications.
  • a method for producing such diamond includes the steps of:
  • a method for producing devices of silicon or other semiconductors or other materials, of micro or nanoscale dimensions, typically called MEMS, by building the device with ultrafine particles rather than substractively forming the device from solid semiconductor material with etching or other methods includes the steps of:
  • a method for producing fine SiC of a size less than 1 micron and including down to 0.001 microns using larger particles of SiC includes the steps of:
  • a method for producing fine A12O3 being of a size less than 1 micron and including down to 0.001 microns using larger particles of A12O3 includes the steps of:
  • feed particles Such large particles are typically much cheaper to procure than fine particles of A12O3. These particles are termed "feed particles.”
  • carrier fluid such carrier fluids being specified by the application and including water, oil , and organics, with the degree of concentration of particulate material in the fluid being specified by the application.
  • a method for producing fine tungsten particles of a size less than 400 x 10 "9 meters and including down to 1 x 10 "9 meters using larger particles of tungsten including the steps of:
  • nitriding the feed material such nitride being known to be brittle, by known methods of nitriding such as heating tungsten in dissociated ammonia at 500 degrees C for a length of time proportionate to the feed material size but sufficient to cause nitridation;
  • a method for producing tungsten components, or tungsten alloy components, from the fine tungsten particles produced by the method detailed in the preceding paragraph includes the steps of:
  • a method for producing fine molybdenum particles of a size less than 400 x 10 "9 meters and including down to 1 x 10 "9 meters using larger particles of molybdenum includes the steps of:
  • nitriding the feed material such nitride being known to be brittle, by known methods of nitriding such as heating molybdenum in dissociated ammonia at about 500 degrees C for a length of time proportionate to the feed material size but sufficient to cause nitridation;
  • a method for producing molybdenum or molybdenum alloy components from particles produced according to the method of the preceding paragraph include the steps of:
  • a method for producing fine cobalt particles or cobalt nitride particles being of a size less than 5 microns and including down to 1 x 10 *9 meters using larger particles of cobalt includes the steps of:
  • a method for producing fine metal particles from metal nitrides including the steps of:
  • a method for producing fine metal particles or metal hydride particles from metal hydrides such as titanium and tantalum, being of a size less than 30O x 10 "9 meters and including down to 1 x 10 "9 meters using larger particles of metals includes the steps of:
  • Spheres according to the present invention were formed by taking material composed of Ti, W, and C and preparing spheres 150 microns in diameter.
  • the test composition in this example was 86.7 wt% tungsten, 4.5 wt% carbon, and the balance titanium. Agglomerates of particulates of this test composition were spheridized in an RF Plasma spray unit. The density of the material was confirmed as being the same as the multi- carbide material that was sought to be made.
  • the multi-carbide spheres of the present invention were then subjected to hardness testing.
  • a compression test was employed in which a single small sphere was isolated between two pieces of ground tungsten plate and a force was applied to one of the plates. The intention was to increase the applied pressure until the sphere fragmented due to the extreme load at the point contact between the plate and the sphere.
  • spheres of the test composition did not fracture, but instead embedded into the tungsten plate, demonstrating hardness of the test material well above that of pure tungsten.
  • a second test several spheres were positioned between two tungsten plates and the top plate was struck with a weight so as to induce high transitory g- forces on the spheres.
  • the multi-carbide spheres were subjected to mechanical toughness testing. Spheres of the test composition were placed in a vibratory mill with calcium carbide and agitated for a period of time sufficient to cause significant grinding media degradation by all known grinding media. No evidence of contamination by grinding media degradation was observed from such use of the resultant spheres, and very fine, regular and pure calcium carbide was obtained.
  • the multi-carbide spheres were also subjected to testing by use in standard industry processes.
  • the spheres were used in a high-volume media mill and operated under nominal industrial production conditions used to mill titania. Titania is particularly sensitive to discoloration from contamination and was chosen to be a sensitive indicator to see if the microspheres were able to impart wear without themselves wearing significantly.
  • Billions of particles of titania were processed to a final particle size of approximately 7 x 10 ⁇ 8 meters without perceptible evidence of grinding media degradation.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
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  • Crushing And Grinding (AREA)

Abstract

L'invention concerne des particules fines de taille prédéterminée comprise entre 1 x 10-9 mètres et 20 microns qui sont produites à partir de particules d'alimentation plus grandes du matériau par traitement de ces particules d'alimentation dans un broyeur, les corps broyants étant des particules polycarbure. Le polycarbure présente une masse volumique excédant 8 gm/cc et une dureté et ténacité suffisantes pour éviter une contamination des particules d'alimentation traitées à un degré maximal supérieur à environ 100 jusqu'à environ 900 ppm. Le traitement se situe à une intensité d'énergie susceptible de provoquer la réduction de la taille des particules d'alimentation pendant une période qui permet de réduire efficacement la taille particulaire au niveau de la taille prédéterminée. D'autres matériaux peuvent également être traités au moyen des sphères afin d'obtenir des tailles particulaires inférieures jusqu'à 1 x 10-9 mètres.
PCT/US2005/007744 2004-03-10 2005-03-09 Procedes d'utilisation de corps broyants polycarbure Ceased WO2006014187A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/797,343 US7140567B1 (en) 2003-03-11 2004-03-10 Multi-carbide material manufacture and use as grinding media
US10/797,343 2004-03-10

Publications (2)

Publication Number Publication Date
WO2006014187A2 true WO2006014187A2 (fr) 2006-02-09
WO2006014187A3 WO2006014187A3 (fr) 2006-04-13

Family

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Family Applications (2)

Application Number Title Priority Date Filing Date
PCT/US2005/007744 Ceased WO2006014187A2 (fr) 2004-03-10 2005-03-09 Procedes d'utilisation de corps broyants polycarbure
PCT/US2005/007743 Ceased WO2005086853A2 (fr) 2004-03-10 2005-03-09 Procede de fabrication de materiaux polycarbure et utilisation

Family Applications After (1)

Application Number Title Priority Date Filing Date
PCT/US2005/007743 Ceased WO2005086853A2 (fr) 2004-03-10 2005-03-09 Procede de fabrication de materiaux polycarbure et utilisation

Country Status (1)

Country Link
WO (2) WO2006014187A2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013530198A (ja) * 2010-07-07 2013-07-25 エフ．ホフマン−ラ ロシュ アーゲー 複素環式抗ウイルス化合物

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Publication number Priority date Publication date Assignee Title
US2113353A (en) * 1937-12-13 1938-04-05 Philip M Mckenna Tungsten titanium carbide, wtic
US5663512A (en) * 1994-11-21 1997-09-02 Baker Hughes Inc. Hardfacing composition for earth-boring bits
DE60133270T2 (de) * 2000-05-10 2009-04-23 Jagotec Ag Zerkleinerung mittels mahlkörper
DE60137943D1 (de) * 2000-08-31 2009-04-23 Jagotec Ag Gemahlene partikel
DE10130860C2 (de) * 2001-06-28 2003-05-08 Woka Schweistechnik Gmbh Verfahren zur Herstellung von sphäroidischen Sinterpartikeln und Sinterpartikel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013530198A (ja) * 2010-07-07 2013-07-25 エフ．ホフマン−ラ ロシュ アーゲー 複素環式抗ウイルス化合物

Also Published As

Publication number Publication date
WO2005086853A3 (fr) 2006-07-06
WO2005086853A8 (fr) 2006-10-19
WO2005086853A2 (fr) 2005-09-22
WO2006014187A3 (fr) 2006-04-13

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