DE2845834A1 - COMPOSITE MATERIAL MADE FROM A POLYCRYSTALLINE DIAMOND BODY AND A SILICON CARBIDE OR SILICON NITRIDE SUBSTRATE, AND A PROCESS FOR THE PRODUCTION THEREOF - Google Patents

Description

The invention relates to a composite material made of a polycrystalline Diamond body and a silicon carbide or silicon nitride substrate. The invention also relates to a process for the production of a composite material of the aforementioned kind, in which a dense mass of diamond crystals with a silicon carbide or silicon nitride substrate connected is. The diamond crystals are bonded to each other and by a binder containing silicon atoms bonded to the silicon carbide or silicon nitride substrate.

A technical obstacle to a high density diamond compact that has a high volume of diamond and has been produced under the diamond-stable pressure range, the development of a suitable one was necessary Binding agent, which is in the capillaries of a tightly packed diamond powder consisting of fine particles penetrates. The binder must and should enter into a thermally stable, firm bond with the diamond Do not graphitize the diamond or react excessively with the diamond.

According to the invention, one containing a eutectic silicon-rich alloy is used, which fits well into the capillaries of a molding compound made of diamond crystals penetrates and wets the diamond crystals, so that a diamond body with an excellent bond is created. The impregnating alloy also provides a strong bond in situ with a silicon carbide or silicon nitride substrate

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here. Eei the method according to the invention are also Pressures applied which are substantially below those of the diamond stable The range of pressures needed to create a composite material from a polycrystalline diamond body and a silicon carbide or silicon nitride substrate in a variety of configurations and in a wide variety Manufacture size range. The composite material can be used as an abrasive, cutting tool, nozzle or other Wear-resistant component can be used.

The inventive method for producing a Comprises composite material of a polycrystalline diamond body and a silicon carbide or silicon nitride substrate a hot pressing process and a procedural measure in which in a container serving as a shield or Cup of a solid mass made of a silicon-rich alloy or solid components containing a eutectic for the formation of a silicon-rich alloy containing eutectic as well as a diamond crystal mass and a silicon carbide or silicon nitride substrate are introduced in such a way that the diamond crystal mass is between the substrate and the mass of solids from the eutectic-containing, silicon-rich Alloy and the diamond crystal mass with the substrate and the solid mass from the eutectic containing, silicon-rich alloy or with at least one of the components for the formation of the eutectic-containing, silicon-rich alloy is in contact. The silicon-rich alloy containing the eutectic is made of silicon and a metal which forms a silicide with silicon. The container and its contents are in one Arranged pressure-transmitting powder medium which transmits an applied pressure and essentially unabated remains essentially unsintered during the hot-pressing process. The powder medium is placed on the container and its content is essentially isostatic pressure

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practiced, which is sufficient to stabilize the dimensions of the container and the contents substantially evenly and thereby creating a dimensionally stable, substantially isostatic system of the powder-coated container. the The density of the resulting pressed material from diamond crystals is more than 70 percent by volume of the volume of the pressed one Diamond crystals. The resulting, essentially isostatic system is subjected to a hot pressing process, to form a liquid, eutectic-containing, silicon-rich impregnation alloy and the liquid, eutectic-containing, float silicon-rich alloy into the spaces between the molding compound made of diamond crystals and with to bring the contact surface of the substrate into contact. The hot pressing process is carried out at a hex pressing temperature carried out below 1600 ° C under a hot pressing pressure, which is used to float in the liquid, silicon-rich alloy sufficient in the interstices of the pressed diamond crystal mass. The eutectic containing, silicon-rich Solid alloy or the solid components to form the eutectic-containing, silicon-rich alloy used in an amount that at the hot-pressing temperature to form a liquid, eutectic-containing, silicon-rich alloy is enough, which is enough to fill the gaps the molding compound of diamond crystals and to touch the contact surface of the substrate. That Hot pressing is carried out in an atmosphere that does not have any noticeable adverse effect on the diamond crystals or the liquid, silicon-rich impregnation alloy penetrating into the diamond crystal mass or on the silicon carbide or silicon nitride substrate. During the hot pressing process, less than 5 percent by volume of the diamond crystals are in not converted to diamond-shaped elemental carbon. The non-diamond shaped carbon or the surfaces of the diamond crystals react with the liquid, silicon-rich impregnating alloy to form carbide. That I

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resulting, hot-pressed, essentially isostatic system is kept under pressure during the cooling process, which is sufficient to at least substantially maintain the dimensions of the hot-pressed system. That I resulting composite material of a polycrystalline diamond body and a silicon carbide or silicon nitride substrate is obtained with the diamond crystals in an amount of at least 7o volume percent of the volume of the bound polycrystalline diamond body are present.

In another embodiment of the invention In the process, no container or cup serving as a shield is used. In this embodiment, the solids mass of the eutectic containing, silicon-rich alloy or the solid components to form such an alloy as well as the diamond mass and the silicon carbide or silicon sodium substrate placed directly in a preformed cavity having a predetermined size was previously molded in a pressure-transmitting powder medium. The cavity can be inserted in a number of ways Powder to be molded. For example, the pressure-transmitting powder medium can be placed in a die Rigid mold of the desired size inserted into the powder and the resulting system at ambient temperature be compressed under a pressure that is sufficient to bring the powder into a stable form, that is, the To give pressed powder sufficient strength, so that after removal of the molding tool in the powder Cavity remains, which is used as a container for receiving the silicon carbide or silicon nitride substrate, the diamond mass and the silicon-rich alloy. When the silicon carbide or silicon nitride substrate, the diamond mass and the silicon-rich alloy has been introduced into the cavity under the condition that the diamond mass is present

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is located between the substrate and the alloy, the cavity is covered with further pressure transmitting powder and the entire system is cold-pressed at ambient temperature in order to respect the cavity and its contents To stabilize dimensions and an essentially isostatic system for the powder-enclosed cavity to create with content.

The invention is explained in more detail below with reference to drawings. In the drawings show:

1 shows a section of a state diagram of a silicon-zirconium alloy with the Equilibrium diagram for a silicon-rich zirconium alloy containing a rutectic, which is suitable for the invention,

2 shows a cross section through a cell consisting of a container and its contents, which is intended to be flooded in the silicon-rich alloy according to the invention is used,

3 shows a schematic representation of a device for exerting a slight pressure on the cell shown in Fig. 2, the cell is set in vibration to increase the packing density of the diamond crystals,

4 shows a cross section through a device for exercising an at least substantially isostatic Pressure on the cell with the help of a pressure-transmitting powder medium to to stabilize the dimensions of the cell and to create an essentially isostatic system

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create,

5 shows a cross section through a graphite mold for the simultaneous application of heat and pressure, i.e. for hot-pressing the essentially isostatic system with the enclosed cell,

Pig. 6 is a side view of one according to the invention

composite material made of polycrystalline diamond body and silicon carbide or silicon nitride substrate, and

Fig. 7 is a photomicrograph (69o magnification) a polished cross-sectional area of a composite material produced according to the invention.

According to the invention, a layer structure is formed in which the diamond crystal mass between a silicon carbide or silicon nitride substrate and a solid mass of a eutectic-containing, silicon-rich alloy and is in contact with the substrate and the alloy. When carrying out the inventive In the process, the layer structure is subjected to a cold pressing process at ambient or room temperature in order to achieve the To stabilize the dimensions of the layer structure substantially uniform. The layer structure is then a Subjected to hot pressing, in which from the silicon alloy a liquid, silicon-rich alloy is created, which is embedded in the mass of compressed diamond crystals is flooded in and brought into contact with the silicon carbide substrate.

In another embodiment, the diamond

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crystal mass are in contact with at least one of the components that are rich in silicon to form the eutectic-containing Alloy is used in situ. This means that the diamond crystal mass can also be made with silicon or alloy metal stand in touch. The silicon carbide or silicon nitride substrate, the diamond crystal mass as well the components for the formation of the silicon-rich alloy are first cold-pressed at ambient or room temperature in order to essentially stabilize their dimensions, and then hot-pressed, a liquid, eutectic-containing, silicon-rich alloy being formed and in the mass of compressed diamond crystals flooded in and with the silicon carbide or silicon nitride substrate is brought into contact. The components for forming the silicon alloy are arranged so that the formation of the silicon alloy begins before hot pressing, i.e. before the hot-pressing temperature is reached.

The mass of the diamond crystals, the mass of the silicon-rich starting alloy present in the solid phase or the solid components to form the silicon-rich alloy and the silicon carbide or silicon nitride substrate can take a variety of shapes. For example, any Mass are present in the form of a layer, with the layer of diamond crystals lying between the other layers. The silicon-rich starting alloy can also be in the form of a tube or a cylinder with a continuous Have core. The alloy tube is cast so that it fits snugly against the inside wall of the container. The substrate may be in the form of a rod placed in the center of the core of the tube made of the silicon alloy is in the annular space between the silicon alloy tube and the substrate rod Biamant crystals are packed.

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In the process according to the invention, natural as well as synthetic, i.e. artificial diamond crystals can be used. The diamond claws have in the direction of its greatest extent a size in the area from about "1 to about 1OCO microns, being the compress or the grain sizes largely depend on the desired packing density of the diamond crystals and also on the intended use of the resulting diamond body. If the Diamond bodies can be used, for example, for grinding purposes diamond crystals that are no larger than about 60 micrometers are preferred. To achieve an optimal Packing of the diamond crystals in the method according to the invention, the crystals should be graded in size and include a range of grain sizes in which small, medium and large crystals are included. In the The size of the graded crystals range from about 1 to about 60 micrometers, preferably within this size range about 6o to about 50 percent by volume of the total crystal mass in the upper part of the particle size range, about 5 to about 10 percent by volume of the middle part of the Particle size range.es and the rest the lower part of the Belong particle size range.

The size of the diamond crystals is facilitated by shaving the larger diamond crystals in a jet mill. The diamond crystals are preferably chemically cleaned to evt. Oxides or other "impurities from the surface to be removed before the diamond crystals used in the process according to the invention. This can be done in that the diamond crystals in hydrogen at about 9oo ⁰ C for about one hour be heated for a long time.

The method used in the present invention, in

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solid phase present, a eutectic containing, silicon-rich The starting alloy, i.e. an alloy that also includes an intermetallic compound, consists of silicon and a metal, that is, an alloy metal that forms a silicide with silicon. Its a eutectic containing, silicon-rich alloy consists preferably of silicon and a metal from the group that Cobalt (Co), chromium (Cr), iron (Fe), hafnium (Hf), manganese (Mn), molybdenum (Mo), niobium (Nb), nickel (Ni), palladium (Pd), platinum (Pt), rhenium (Re), rhodium (Rh), ruthenium (Ru), Tantalum (Ta), thorium (Th), titanium (Ti), uranium (U), vanadium (V), tungsten (W), yttrium (Y), zirconium (Zr), and mixtures from this includes.

The silicon-rich starting alloy containing a eutectic is solid at room temperature and contains more than 50 atomic percent but less than 100 atomic percent Silicon. The starting alloy usually contains a maximum of about 99 »5 atomic percent silicon, with the silicon content depends largely on the specific effect the alloying metal has on the resulting silicon-rich Alloy has. The silicon-rich alloy present in the solid phase contains a eutectic, i.e. a certain one eutectic structure, and can be of hypoeutectic, hypereutectic or eutectic composition. 1 it can be seen, for example, that the eutectic (2) is an alloy with a special composition is that under equilibrium conditions on cooling at constant temperature to a solid with solidifies at least two phases and completely melts when heated at the same constant temperature. These constant temperature is referred to as the eutectic temperature, which is also represented by the reference symbol (2) is. The eutectic (2) is the composition in which two falling liquidus curves (3) and (4) am

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eutectic point (2) coincide. The butectic (2) therefore has a lower melting point than the neighboring hypoeutectic or hypereutectic compositions. The liquidus curve or liquidus line in a state diagram represents under equilibrium conditions represent the temperatures at which the silicon alloy stops melting on heating and solidifies on cooling begins. The solid phase used in the process according to the invention, containing a eutectic, Silicon-rich alloy is an alloy of a number of alloys on a eutectic horizontal (1), that is, one passing through the eutectic point (2) Horizontals emanating from any alloy, the composition of which is to the left of the eutectic point (2) lies in an equilibrium diagram and contains something eutectic, i.e. is hypoeutectic, and up to any alloy whose composition is to the right of the eutectic point (2) in the equilibrium diagram and contains something eutectic, i.e. it is hypereutectic.

The solid, silicon-rich starting alloy may or may not have the same composition as the to have silicon-rich impregnating alloy. If the entire, in solid form, silicon-rich starting alloy - tion becomes liquid at the hot-pressing temperature, it has the same composition as the silicon-rich impregnation alloy, But only part of the silicon-rich starting alloy, i.e. the hypoeutectic or hypereutectic If the alloy becomes liquid at the hot-pressing temperature, the starting alloy does not have the same composition viie the liquid, silicon-rich impregnation alloy. In this case, the silicon-rich impregnation alloy is richer of silicon as the hypoeutectic output alloy, but poorer in silicon than the hypereutectic, silicon-rich

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Base alloy.

From Fig. 1 it can be seen that the composition of the Remäss of the invention used, a silicon-rich impregnating alloy containing a eutectile and its melting temperature lies on the liquidus curves (3) and (4) and includes the eutectic point (2). The one limited by (1), (2) and (4) Area (5) comprises a solid phase (Si) and a liquid phase, i.e. a liquid impregnating alloy, whereby the amount of the solid phase increases and the amount of the liquid phase decreases accordingly as the distance from the eutectic Point (2) to the right along the horizontal (1) increases, i.e. when the amount of silicon in the alloy increases above the eutectic amount. The area (6) bounded by (1), (2) and (3) similarly comprises one solid phase ZrSip and a liquid phase, i.e. a liquid impregnation alloy, whereby the amount of the solid phase increases and the amount of the liquid phase decreases accordingly when the distance from the eutectic point (2) to left along the horizontal (1) increases, i.e. when the amount of silicon in the alloy falls below the eutectic Amount is decreasing.

In the method according to the invention are the desired Composition of the silicon-rich impregnating alloy containing a eutectic and its melting temperature at a point on the liquidus curves of the phase diagram containing the eutectic point for the according to the invention Process used silicon-rich alloy. The hot-pressing temperature is the temperature in which the desired composition of the silicon-rich impregnating alloy is liquid, i.e. in a sufficient flowable state is present in order to be able to penetrate into the compressed diamond mass. If as solid starting material an alloy rich in silicon

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is used, which has the same composition as the desired impregnation alloy, is the hot-pressing temperature the temperature at which the alloy is liquid. The hot-press temperature door is in a range of approx 10 ° G to preferably a maximum of about 100 ° G above the melting point the alloy. Depending on the alloy currently used, however, hot-pressing temperatures can also be used, which are above this preferred maximum. Hot-pressing temperatures above 1600 ° C are not suitable because in this case, a tendency to excessive graphics the diamond is made.

However, if the starting alloy is not the same composition like the desired impregnating alloy, but heated to the melting point of the desired impregnating alloy an impregnation alloy is created as a liquid phase. The hot-pressing temperature is then a temperature at which the penetrating alloy phase is formed in liquid form, which is at about 1o 0 above the melting point of the penetrating Alloy phase is the case.

As can be seen from Fig. 1, the melting point of a certain impregnation alloy with a hypereutectic composition is on the liquidus line 4. For example, if the desired hypereutectic impregnation alloy contains 95 atomic percent ISi, the melting point on the liquidus line is about 1400 ° G, as indicated by the line 7 is shown. If the silicon-rich starting alloy has the same composition as the desired penetrating impregnating alloy, represented by line 7, the entire starting alloy would melt at the melting temperature of 1400 G and the liquefaction or hot-pressing temperature would be from about 1410 ° G to preferably about 15IO ⁰ C or optionally down to below 1600 ° G.

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However, if the source alloy rich in silicon is any is hypereutectic alloy, which in the equal weight diagram of FIG. 1 on the horizontal 1 to the right of the Line 7 is »the hot-pressing temperature is the temperature in which the desired penetrating impregnating alloy of 95 atomic percent Si and 5 atomic percent Zr is brought into liquid form becomes, which would be the case at around 1410 C.

At the hot-pressing temperature, the starting alloy should also be used the desired penetrating impregnating alloy can be produced in liquid form in an amount that is sufficient, to fill the cavities of the compressed diamond mass, the crystal density of which is over 70 percent by volume and to bring the soaking liquid into contact with the contact surface of the silicon carbide substrate, so that the pores or voids at the interface between the polycrystalline body and the one with the polycrystalline Body in contact with the substrate are filled and the resulting composite material is pore-free or has at least an essentially pore-free interface. The liquid impregnating alloy should be at the hot-pressing temperature can be produced practically in an amount of at least about 1 percent by volume of the silicon-rich starting alloy.

The hot pressing process is carried out at a temperature at which the silicon-rich impregnating alloy is liquid, carried out under a pressure that only needs to be sufficient, around at the hot-press temperature * in the diamond mass between opposite diamond surfaces to tear open existing intermediate layers, which prevent the penetration of the liquid Prevent alloying into the interstices of the diamond mass.

This usually requires a minimum pressure of about 35 kgf / cm. The hot pressing pressure can in particular be approximately

35 "to about 1410 kp / cm. The hot press pressure is

but usually in the range of about 70 to about 700 kgf / cm

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2 Ileiss press pressures bring about 1410 kp / cm in the process according to the invention no noticeable advantages.

With a temperature at which the penetrating impregnation alloy is liquid, what is meant here is a temperature at which the impregnation is able to flow readily. When the impregnating alloy is at its melting point, which is represented by the Liauidus line or, in the case of a eutectic alloy, by the eutectic point the penetrating adhesive is a thick, viscous mass. However, if the temperature is above the If the melting point rises, the drinking liquid becomes less viscous. At a temperature that is about 10 C above the melting point the liquid impregnating alloy becomes easily flowable, i.e. liquid. The temperature at which the silicon-rich Impregnation alloy is liquid, is the temperature at which the impregnation alloy enters the capillary-like channels, Interstices or pillars of the compressed diamond crystal mass penetrates whose crystal density is over 70 percent by volume lies. With a further increase in temperature, the flowability of the liquid, silicon-rich one decreases Impregnation alloy too, which leads to a more rapid penetration of the alloy into the diamond crystal mass. At one temperature from about 100 ° C above the melting point, the impregnating alloy usually has its highest flowability, so that Temperatures above this flea temperature usually do not need to be used.

The silicon-rich alloy with eutectic composition melts at a temperature below about 1430 ° C For the group of high-silicon alloys preferred here, the eutectic melting point of 870 ° C is sufficient for a eutectic SiPd alloy with about 56 atomic percent Si up to 1410 ° C for a eutectic SiMo alloy with about 97 atomic percent Si. From Fig. 1 it can be seen that the

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eutectic SiZr alloy (2) contains 9o.4 atomic percent Si and has a eutectic melting temperature of 1360 ° C. The predominant phase of those present in solid form silicon-rich, eutectic alloy is almost pure silicon.

The penetrating, containing a eutectic, silicon-rich Tränklegierung has a melting point below about 1500 ° C, usually from about 85O ⁰ C to about 145 ° ⁰ C. The temperature at which the Tränklegierung becomes liquid, is at least about 10 C above the melting point.

The solid, silicon-rich starting alloy or the solid components for forming the silicon-rich alloy can be in solid or powdered form. The amount of solid, silicon-rich starting alloy can, depending on the achievable amount of the liquid, silicon-rich impregnating alloy and vary from the capacity of the device. Generally, the amount of the high silicon impregnating alloy will be in the range of about 25 percent by volume to about 80 percent by volume, but to achieve optimal results preferably in the range of about 30 to about 60 percent by volume the compressed diamond crystal mass, the crystal density of which is over 7 ο percent by volume.

The hot-pressing process is carried out in an atmosphere that has no noticeable harmful influence on the Diamond crystals or the silicon-rich impregnation alloy or the silicon carbide substrate. The hot pressing process can be carried out under vacuum or in an inert gas such as argon or helium or else in nitrogen or hydrogen will. The hot-pressing process is carried out sufficiently quickly so that no noticeable reaction between the

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silicon-rich impregnating alloy and nitrogen or hydrogen takes place. The hot pressing process cannot be carried out in air because the diamond is at one temperature Slightly graphitized in air above 800 ° C and the liquid, silicon-rich impregnation alloy oxidize and solid Silica would form before any appreciable amount of liquid alloy penetrated the diamond mass.

The silicon carbide substrate is a polycrystalline body with a density of about 85 to about 10 ^ percent of the theoretical density of silicon carbide. The density of silicon carbide given here is the partial density based on the theoretical density for silicon carbide of 3.21 g / cm- ⁵ . A silicon carbide, polycrystalline body with a density below about $ 85 is not suitable because it would not have the necessary mechanical strength for most applications, for example for a tool insert. The higher the density of the silicon carbide body, the higher its mechanical strength is usually also.

The silicon nitride substrate is a polycrystalline body having a density in the range from about 50 to about 100 # the theoretical density of silicon nitride. The silicon nitride density given here is a fraction of the density based on the theoretical density for silicon nitride of 3.18 g / cm. A polycrystalline body made of silicon nitride with a density below So i ° is not suitable, since such a polycrystalline body would not have the required mechanical strength for most purposes, for example for use as a tool insert. Usually, the higher the density of the silicon nitride body, the higher its mechanical strength.

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The polycrystalline substrate made of silicon carbide or silicon nitride is a hot-pressed or sintered body, the silicon nitride, i.e. silicon nitride in an amount of at least 90 percent by weight and usually at least 95 percent by weight and generally in the range of 96 percent to 99 percent by weight or more based on the weight of the substrate body contains. All components used in addition to the silicon nitride or Components of the polycrystalline silicon nitride-containing body should not have any appreciable adverse influence on the mechanical properties of the resulting composite material. In particular, these ingredients should and components do not noticeably adversely affect the properties of silicon nitride and the like the other materials used in the method according to the invention for producing the composite material on the properties of the composite material itself.

The silicon carbide body used according to the invention can be made by the sintering processes described in U.S. Patent 4,004,934 and U.S. Patent Applications 681 7.06 of April 29, 1976 and 707.117 of July 21, 1976.

The silicon carbide sintered body can thereby be manufactured that a submicron particle mixture of B-silicon carbide, boron additive and a carbonaceous additive formed in the form of free carbon or a carbonaceous organic material that decomposes under heat and releases carbon generated ^ and that a so-called green body is formed from this mixture. Another method is a submicron particle mixture of "A-silicon carbide, which is the average particle size twice as large as the mixture of B-

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Silicon carbide is admixed with the particle mixture of B-silicon carbide in an amount of 0.05 to 5 percent by weight, based on the B-silicon carbide. The G-rünkörper is sintered to the required density at a temperature in the range of about 1900 ⁰ C to 2300 ⁰ C.

The boron additive can be in the form of an elemental boron carbide or a boron compound, which can be found in a temperature below the sintering temperature and boron or boron carbide and gaseous decomposition products provides and is used in an amount based on an amount of 0.3 to 3 weight percent elemental boron is equivalent to the amount of silicon carbide. During the sintering process, the boron additive goes into a solid solution with the silicon carbide over. When the crowd of the additive exceeds the equivalent value by about one percent by weight of elemental boron, a boron carbide phase also occurs the end.

The carbonaceous additive is used in an amount equivalent to about an amount of 0.1 to about 1.0 percent by weight of free carbon based on the amount of silicon carbide. The additive may be free carbon or a solid or liquid carbonaceous organic material which completely at a temperature of 50 ° C to 1000 ⁰ C decomposes in a lying in the submicron range, free carbon and gaseous decomposition products. Examples of carbon-containing additives are polymers of aromatic hydrocarbons, such as polyphenylene or polymethylphenylene, which are soluble in aromatic hydrocarbons.

The sintered body consists of silicon carbide, about 0.3 to about 3 weight percent boron, and up to about one Percent by weight of free carbon, whereby the

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given percentages by weight on the amount by weight of silicon carbide relate. The boron is in solid solution with the silicon carbide or as a boron carbide phase in solid solution with the silicon carbide. If the free carbon is detectable, it is in the form of submicron particles before, which are distributed over the entire sintered body.

The hot-pressed silicon carbide bodies can preferably be produced by methods described in FIG US Pat. No. 3,853,566 and in US Pat. No. 695,246 dated June 11, 1976 are described.

A dispersion of a horizontal submicron Silicxumkarbidpulver and a boron or Borkarbidmenge corresponding to an amount of boron of 0.5 to 3.0 weight percent, in a single hot-pressing operation at a temperature of 190O ⁰ G to 2000 ⁰ C under a pressure

from 350 to 7OO kp / cm hot pressed to obtain a boron containing silicon carbide bodies. In another hot-pressing process, the dispersion 0.5 to 3.0 percent by weight of elemental carbon or carbon-containing additives added to the decompose under heat into elemental carbon.

The polycrystalline silicon nitride body can be made by sintering processes described in US patent applications 756 085 and 756 086 of 3.1.1977 are described.

U.S. Patent No. 756085 relates to a sintered one Silicon nitride body which is produced by a homogeneous dispersion of a submicron range lying silicon nitride and a beryllium additive is formed from the group of beryllium, - beryllium carbide,

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Beryllium fluoride, beryllium nitride, beryllium silicon nitride, and mixtures thereof. The beryllium additive is present in an amount in which the beryllium component is equivalent to an amount of from about 0.1 to about 2 percent by weight of elemental beryllium based on the amount of silicon nitride. A green body is formed from the dispersion, which is ^{sintered at a temperature of about 1900 C to about 2200 0} C in a sintering atmosphere formed by nitrogen under a pressure above atmospheric pressure, which prevents a noticeable thermal decomposition of the silicon nitride at the sintering temperature and a Sintered body with a density of at least about 80 $> the theoretical density of silicon nitride can arise. The minimum pressure of the nitrogen is in a range from about 20 atm at a sintering temperature of 190O ⁰ O to about 130 atm at a sintering temperature of 2200 ⁰ G.

The method according to US patent application 756 086 corresponds to the method according to US patent application 75 & 085 with the exception that an addition of magnesium is added to the dispersion of silicon nitride and beryllium addition. The green body is sintered at a temperature of about 18oo ° C to about 2200 ⁰ C in a plane formed by nitrogen sintering atmosphere at a superatmospheric pressure pressure of at least about 1o atmospheres at a sintering temperature of 1800 ⁰ C to at least about 130 atm at a sintering temperature of 2200 ⁰ C. is sufficient. The magnesium additive is selected from the group of magnesium, magnesium carbide, magnesium nitride, magnesium cyanide, magnesium fluoride, magnesium silicide, magnesium silicon nitride, and mixtures thereof. The magnesium additive is used in an amount with the magnesium component in an amount of from about 0.5 to about 4 percent by weight

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of elemental magnesium based on the amount of silicon nitride is equivalent to.

The polycrystalline described in U.S. Patent Application 756,085 Body has a density ranging from about 8o to about 100 # the theoretical density of silicon nitride. The polycrystalline body consists of silicon nitride and beryllium, the amount of which ranges from less than about 0.1 to about less than about 2.0 weight percent of silicon nitride. The one in the US patent application 756 o86 described polycrystalline body corresponds to the polycrystalline body according to the US patent application 756 085 except that it also contains magnesium in an amount ranging from. less than about From 0.5 to less than about 4 percent by weight of the silicon nitride.

The hot-pressed, polycrystalline silicon nitride bodies can be produced by methods described in U.S. Patent Applications 756 083 and 756 084 dated 3/3/1977 are described.

US Patent Application 756 083 relates to a hot-pressed silicon nitride body which is produced by forming a submicron homogeneous powder dispersion of silicon nitride and magnesium silicide, the magnesium silicide being present in an amount ranging from about 0.5 to about 3 Percentage by weight based on the amount of silicon nitride is sufficient. The powder dispersion is hot-pressed in a nitrogen atmosphere at a temperature of about 1600 ° 0 to 1850 ⁰ O under a minimum pressure of about 140 kp / cm. The resulting polycrystalline silicon nitride body has a density of about 80 to about 100 percent of theoretical

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of silicon nitride. The ροIycrystalline body consists of Silicon nitride and magnesium, the amount of which ranges from about 0.3 to about 1.9 percent by weight based on silicon nitride.

US patent application 756 084 relates to a hot-pressed, polycrystalline silicon nitride body which is produced by forming a submicron powder dispersion of silicon nitride and a beryllium additive selected from the group of beryllium, beryllium nitride, beryllium fluoride, beryllium silicon nitride and a mixture thereof is selected, wherein the beryllium component is present in an amount corresponding to an amount of about 0.1 to about 2 percent by weight of elemental beryllium based on the amount of silicon nitride. The dispersion is in a nitrogen atmosphere at a temperature of about 1600 ⁰ C to about 1850 ⁰ O under a minimum pressure of about 140 kp / cm hot-pressed. The resulting polycrystalline silicon nitride body has a density of about 80 $> to about 100 $ the theoretical density of silicon nitride. The polycrystalline body is composed of silicon nitride and beryllium, the amount of which ranges from about 0.1 to about 2.0 percent by weight based on silicon nitride .

The thickness of the silicon nitride substrate may vary depending on the end use of the resulting product Composite material fluctuate. The substrate, however, should be at least sufficiently thick to be a suitable carrier for an attached polycrystalline diamond body is achieved. A suitable one for most purposes Carrier for receiving an attached polycrystalline diamond body is achieved when the silicon nitride substrate is preferably at least twice as thick as the polycrystalline diamond body attached to the carrier.

In the arrangement shown in Figure 2, the cell exists

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from a cup 11, which is a vertical kpeiszylindischen Has wall with a floor. Inside the cup 11 is a disk 12 made of a silicon rich containing a eutectic Alloy, a diamond crystal mass 13 and in contact with the silicon-rich alloy 12 a thick plug 14 is arranged. The thick stopper 14 fits exactly into the cup 11 and serves as a closure Polycrystalline silicon nitride substrate cylinder.

The cup 11 consists of a material that is used during hot pressing is essentially inert, i.e. no appreciable adverse effect on the properties of the diamond body Has. Such a material can be a non-metal such as compressed hexagonal boron nitride be. However, the material is preferably a metal and in particular a metal from the group consisting of tungsten, yttrium, Includes vanadium, tantalum, and molybdenum.

No free space should remain inside the bowl closed with the stopper, which would prevent mixing or Free movement of the content is allowed, so that the content is at least substantially in its original position is subjected to the essentially isostatic pressure in the cold pressing process.

The purpose of using the diamond crystals graded in size is to achieve a maximum packing density of the diamond crystals. As an alternative or additional measure, the arrangement shown in FIG. 3 can also be expedient in order to increase the packing density of the diamond crystals. In the arrangement according to FIG. 3, the cell is placed on an oscillating table 16 and held there during the oscillating movement under a slight pressure of about 3.5 kp / cm ² , so that the diamond crystals can be rearranged accordingly to fill the cavities, whereby the At-

909817/0942

Part of the cavities is reduced and thus the density of the diamond mass is increased to over 70 percent by volume based on the volume of the diamond mass. The required compression can be determined by tests with diamonds of the same grain size in a fixed dimension Form to be carried out.

The cell 1o is then in the manner shown in FIG Cold-pressed at room or ambient temperature, whereby only a pressure needs to be applied that is necessary to achieve it a dimensionally stable, essentially isostatic system is sufficient. The cell 1o is inside the cylindrical Core of a mold 2o arranged. The cell is composed of a mass 19 made of a pressure-transmitting powder medium enclosed. The powder medium consists of very fine particles with a particle size of 160 mesh / cm, whereby again, particles having a particle size of from about 2 to about 20 micrometers are preferred. The pressure transmitting Powder medium remains essentially unsintered under the pressure and temperature conditions used here. That Pressure-transmitting powder medium is, for example, hexagonal boron nitride and silicon nitride. The pressure transmitting Powder medium ensures that an approximately or essentially isostatic pressure is exerted on the cell 1o, where for the cell 1o and its content in terms of its dimensions essentially uniformly stabilized, i.e. compressed, and an essentially isostatic A system of a corresponding shape is created, which contains the cell enclosed by the powder, the density of which is compressed Diamond crystal layer is over 70 percent by volume of the volume of the compressed diamond crystals. The press mold 2o with a ring 22 and a press ram 23 and 23a can be made of tool steel. Of the Ring 22 can optionally be covered on the inside with a sintered card

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biabuch.se 22a, as described in Pig. 4 is shown

2 to enable the application of pressures up to 14,000 kp / cm

possible. Pressures above 14,000 kgf / cm bring no noticeable advantage. Inside of the press die 23, the socket 22a and the press die 23 a delimited space is preferred

2 wise a pressure in the range of approximately 1400 to 7000 kgf / cm

and usually up to 3,500 kp / cm on the pressure transmitting Powder medium exerted when the rams are conventionally operated until the applied pressure is applied has stabilized, as is known in the conventional compaction of powder.

The pressure used in cold pressing can be determined empirically. An increase in pressure above the pressure value, which is a dimensionally stable, essentially isostatic System delivers, results in no additional compression or dimensional stabilization of the cell 1o and its contents.

The pressure-transmitting powder medium, such as the hexagonal boron nitride or silicon nitride, almost leads to a hydrostatic pressure effect when the Pressure is applied to the powder media in an axial direction. Due to the hydrostatic pressure effect, a substantially isostatic pressure is exerted over the entire area of the cell 1o. It is believed that the applied pressure is transmitted essentially undiminished to the cell 1o. The cold pressing process reduces the The size of the cavities so that the capillary-like cavities are optimally formed in the diamond mass. The diamond crystal mass is also reduced to the required packing density of over 70 percent by volume by the cold pressing process brought. This reduction in the volume of the planing space also ultimately results in a reduction in the diamond body Existing content of non-diamond-shaped material

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and results in more closely opposed crystal faces that are effectively connected to one another can.

After the completion of the cold pressing process, the density of the compressed diamond crystals in the cell should be more than 70 percent by volume of the volume of the crystals. The density of the compressed layer of diamond crystal mass is in the range from about 71 to about less than 95 volume percent and often in the range from about 75 to about 90 volume percent of the volume of the diamond crystals. The higher the density of the crystals, the lower the proportion of non-diamond-shaped material between the crystals, so that a correspondingly harder diamond body is created.

The essentially isostatic system 21 of the powder-coated container produced by the cold pressing process is then hot pressed, whereby the system simultaneously adjusts the hot pressing temperature and the hot pressing pressure is subjected.

After the cold pressing process, one of the two press rams 23 or 23a is withdrawn. Now in the form of a solidified molding present, essentially isostatic system 21 is removed from the socket 22 a and given in the graphite mold 3o shown in Fig. 5, which has a hole with the same diameter as the socket 22 a. The transferred system 21 is then enclosed by the wall of the hole 31 and the two graphite stamps 32 and 32a. The graphite mold 3o is provided with a thermocouple 33, which indicates the temperature that is applied to the dimensionally stabilized, essentially isostatic system 21 is applied. The graphite shape 3o with the essentially isostatic system 21 is then in a conventional,

909817/0942

not shown hot-press furnace given. The Ofenksmmer is at least substantially evacuated, which also causes an evacuation of the system 21 with the cell 1o, so that the system 21 and the cell 1o are essentially are under a vacuum in which the hot-pressing process can be carried out. If necessary, can also nitrogen or hydrogen or an inert gas, such as argon, can be introduced into the furnace chamber in order to System located in the furnace chamber with the contents of cell 1o in an atmosphere suitable for hot pressing suspend. While the punch 32 and 32 a in an axial In the direction of the pressure acting, that is, exerting the hot-pressing pressure on the system 21, the temperature is set to one temperature increased, in which a liquid, silicon-rich alloy is formed from the silicon-rich alloy disc 12, which penetrates the diamond mass.

When hot pressing, the hex pressing temperature should be reached quickly. The hex pressing temperature is then below the hot-pressing pressure is usually maintained for at least one minute in order to ensure sufficient impregnation of the Ensure diamond crystal mass. A hot pressing time of about 1 to about 5 minutes is usually sufficient. Since the transformation of diamond into non-diamond-shaped, elemental carbon largely depends on time and temperature and the probability of conversion into non-diamond-shaped, elemental carbon is all the greater is, the higher the temperature and the longer the time at this temperature, the hex pressing process must be carried out before 5 percent by volume of the diamond is not in diamond-shaped, elemental carbon are converted. The extent of the conversion can be determined empirically. When converting 5 or more volume percent diamond In non-diamond-shaped, elemental carbon, a phase of non-diamond-shaped, elemental carbon can optionally

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rem carbon remain in the end product. This phase out Non-diamond-shaped, elemental carbon would have a considerable, detrimental effect on the mechanical Properties of the end product.

The hot-pressing pressure acting on the liquid, silicon-rich impregnating alloy causes the difficult to melt layer or slag, mostly oxide as well as carbide, which is usually between the liquid, silicon-rich alloy and the diamond faces is formed, whereby the capillary-like cavity system is opened and is made available for the silicon-rich alloy, which then enters the cavities due to capillary action penetrates. Tests have shown that the alloy does not penetrate the diamond mass if it is during the hot pressing process and in the case of an alloy present in the liquid state, a pressure is exerted on the system 21 and is maintained, which is insufficient to break up the slag.

When, during hot pressing, the liquid, silicon-rich alloy penetrates the diamond mass and permeates it and comes into contact with the substrate, the liquid alloy envelops the surfaces of the compressed diamond crystals, the liquid alloy with the diamond surfaces or possibly with the resulting, not diamond-shaped elemental carbon under the formation of carbide, which is at least predominantly and usually essentially silicon carbide. During the hot-pressing process, the impregnating alloy also fills the interface between the contact surfaces of the polycrystalline Diamond body and the substrate, which results in a firmly adhering connection in situ. The resulting Product is a one-piece, well-bonded composite material. The impregnating alloy can also be used in the sub-

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Strat penetrate or diffuse into it.

It is particularly important that essentially isostatic conditions are maintained during the hot-pressing process so that when the silicon-rich alloy becomes liquid, the liquid alloy does not get between the Diamond mass 13 and the cup 11 can penetrate and escape to a noticeable extent, but rather into the Diamond crystal mass 13 is forced into it.

After the hot-pressing process has ended, the hot-pressed system 21 should at least cool down Sufficient pressure can be maintained so that the hot-pressed cell 1o essentially becomes one Isostatic pressure is exposed, which is sufficient to maintain the dimensional stability of the system 21. The hot-pressed System 21 is preferably allowed to cool to room temperature. The hot-pressed cell 1o is then removed from the system, whereupon a composite material is obtained in which the polycrystalline diamond body 13 a is connected in situ directly to the substrate 14 a. Possibly Metal adhering to the container or to the outer surfaces of the Composite material excess, squeezed out silicon alloy can in a conventional manner, for example by Sanding removed.

If in the process according to the invention the components can be used in the form of co-extending layers, the resulting composite material a range of shapes, such as the shape of a disk, a square or rectangle, a rod or of an ingot and have a flat surface of bonded diamonds.

When the silicon-rich alloy takes the form of a tube

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or a cylinder with a core therethrough or Has hole and the substrate is in the form of a rod arranged centrally in the core of the tube, and the annular space is packed with diamond crystals between the silicon alloy tube and the substrate rod, has the result Composite material in the shape of a circular rod.

The composite material produced with the method according to the invention has a polycrystalline diamond body as if in one piece by means of a connection formed in situ with a polycrystalline substrate a silicon carbide or silicon nitride body is connected.

The glued-on polycrystalline diamond body of the invention Composite material has diamond crystals bound by a binder containing silicon atoms are firmly connected to each other. The diamond crystals range in size from about 1 to about 1000 micrometers. The concentration the diamond crystals range from at least about 70 to about below 90 percent by volume and often up to about 89 percent by volume the volume of the polycrystalline diamond body. The diamond body contains up to about 30 percent by volume of one Binder containing silicon atoms, which is at least substantially uniform in the polycrystalline diamond body is distributed. The part of the binder which is in contact with the surfaces of the diamond crystals consists at least predominantly made of silicon carbide, i.e. more than 50 percent by volume of that in direct contact with the surfaces the diamond crystals standing part of the binder is silicon carbide. The one with the surfaces of the diamond crystals part of the binding agent in contact preferably consists at least essentially of silicon carbide, i.e. at least about 85 and preferably 100 percent by volume of that in direct contact with the surfaces of the diamond crystals

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The remaining part of the binder is silicon carbide. Of the The diamond body of the composite material according to the invention is pore-free or at least essentially pore-free.

The polycrystalline silicon nitride substrate of the invention The composite material has a density in the range of about 80 to about 100 $ of theoretical density of silicon nitride and contains at least 90 percent by weight of silicon nitride based on the substrate body and is free from components that have a visibly adverse effect on the mechanical properties of the composite material to have.

The polycrystalline silicon carbide substrate of the composite material according to the invention has a density in the range from about 85 to about 100 $> the theoretical density of silicon carbide and contains at least 90 percent by weight silicon carbide based on the substrate body and is free of components that have a noticeably adverse influence on the mechanical properties of the Have composite material.

At the interface between the polycrystalline diamond body and the silicon carbide or silicon nitride substrate the binder ranges from the polycrystalline diamond body to the substrate, at least essentially the pores present in the interface are filled, so that the interface is pore-free or at least substantially is pore-free, which means that the interface voids or pores in an amount of less than 1 percent by volume of the total Volume of the interface, provided that the pores or voids are small and are less than 0.5 micrometers and are sufficiently evenly distributed in the interface so that the pores do not have any noticeably adverse effect on the liability bond in

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the interface. The proportion of pores in the interface is determined by conventional metallographic measures, for example by optically examining a cross section of the composite material. The distribution and the thickness of the binder at the interface essentially correspond to the distribution and thickness of the binder in the polycrystalline diamond body of the composite material. Assuming a polished cross-section of the composite, the average thickness of the binder at the interface would be substantially the same as the average thickness of the binder between the contacting diamond crystals of the polycrystalline diamond body of the composite. Assuming a polished cross-section of the composite material, the maximum thickness of the binder at the interface would also essentially correspond to the thickness of the binder between the largest, contacting diamond crystals of the polycrystalline diamond body of the composite material. The maximum thickness of the binding agent at the interface is therefore approximately <? 0 percent of the largest dimension of the diamond crystals in the polycrystalline diamond body, if the diamond crystals are measured along their longest dimension. The silicon carbide substrate can also contain binding agents which are present in the form of the impregnating alloy that penetrated and diffused into the substrate during the hot-pressing process.

The binder containing silicon atoms always contains silicon carbide. In one embodiment, the binder consists made of silicon carbide and metal silicide. In another embodiment, the binder consists of silicon carbide, Metal silicide and elemental silicon. In a further embodiment, the binder consists of silicon carbide, Metal silicide and metal carbide. In a further embodiment, the binder consists of silicon carbide,

909817/0942

Metal silicide, metal carbide and elemental silicon. In yet another embodiment, the binder is made made of silicon carbide, metal carbide and elemental silicon. In the case of the metal components of the metal silicide and metal carbide in the binder according to the invention it is the alloy metal or metals that are in the impregnation alloy are present.

The metal component of the metal silicide in the binder is preferably selected from the group consisting of cobalt, Chromium, iron, hafnium, manganese, rhenium, rhodium, ruthenium, Includes tantalum, thorium, titanium, uranium, vanadium, tungsten, yttrium, zirconium, and alloys of these metals.

The metal component of the metal carbide present in the binder is a strong carbide former, which results in a stable carbide, and preferably a metal from the group consisting of chromium, hafnium, titanium, zirconium, Includes tantalum, vanadium, tungsten, molybdenum, and alloys of these metals.

The proportion of any elemental silicon and silicon carbide present in the binder of the adhered polycrystalline diamond body can depending on the extent of the reaction between the faces of the diamond crystals and the silicon-rich impregnating alloy as well as depending on the extent of the reaction between the non-diamond-shaped, elemental carbon and the silicon-rich impregnation alloy vary. Assuming all other factors are the same, the amount of silicon carbide present in the binder depends on the bonded polycrystalline diamond body largely on the hot-pressing temperature and the dwell time at this temperature. If the dwell time and / or temperature is increased, the proportion of silicon carbide increases while the proportion of elemental silicon decreases

909817/0942

or reduced to an undetectable value will. You can therefore, for example, empirically determine the process conditions that must be complied with, a polycrystalline diamond body with a silicon carbide content to achieve which leads to the desired properties.

The binder in the glued-on polycrystalline diamond body always contains at least a detectable amount of Silicon carbide and at least a detectable amount of Silicide and / or carbide of the alloy metal present in the impregnation alloy. The metal silicide is depending on of the alloy used is usually in the form of a disilicide. The binder can also have at least one detectable Amount of elemental silicon contained. With detectable amount of silicon carbide, metal silicide, metal carbide or elemental silicon is meant that amount that is transmitted through an electron microscope of a thin part of the diamond body can be detected due to the electron beam diffraction that occurs can. However, the binder in the diamond body generally contains silicon carbide in an amount of about 1 to about 25 percent by volume based on the volume of the polycrystalline Diamond body and generally metal silicide in at least a detectable amount and often one minimum amount of about 0.1 volume percent of the polycrystalline diamond body. The amount of metal silicide present depends largely on the composition of the impregnating alloy rich in silicon. The metal silicides are hard and have often lower, linear thermal expansion coefficients than the metals or in some cases than diamond, such as rhenium, such a property being desirable for a phase in a diamond body. The respectively The amount of silicon carbide and elemental silicon present depends largely on the composition of the silicon

909817/0942

high-calcium impregnating alloy and the extent of the reaction between the high-silicon alloy and a diamond-shaped one or non-diamond shaped carbon. The amount of metal carbide present in each case largely depends on the composition of the silicon-rich impregnating alloy.

The electron beam diffraction when irradiating a thin section of the composite material with the aid of a Electron microscope shows that the part of the binder that is in contact with the faces of the diamond crystals consists at least predominantly of silicon carbide.

The polycrystalline diamond body is pore-free or at least essentially pore-free, ie it can contain cavities or pores of less than 1 percent by volume based on the volume of the " ¹ body, provided the cavities or pores are small, ie below 0.5 micrometers and sufficiently uniform in size Bodies are distributed so that they have no visibly adverse effect on the mechanical properties of the diamond body. The void or pore content of the polycrystalline diamond body is determined by conventional metallagraphic measures, for example by optically examining a polished cross section of the body.

The diamond body according to the invention is also in this respect free of a non-diamond-shaped carbon phase when it is not a non-diamond-shaped, elemental carbon phase in an amount detectable by an X-ray diffraction analysis.

A particular advantage of the invention is that the polycrystalline diamond body of the composite material in A variety of sizes and shapes can be made, for example, the diamond body can be a width or length

909817/0942

of up to 25 mm or more. Polycrystalline Diamond bodies which are longer than 25 mm and have a diamond density according to the invention are practically impossible be produced with processes in which ultra-high pressures and temperatures of the diamond-stable range in the State diagram of carbon are used, since the necessary to achieve and maintain such high pressure and temperature conditions require an extremely complex structure and therefore only have a limited capacity. On the other hand, the glued-on, polycrystalline diamond body can be so small or be thin as desired. However, the diamond body will always have a thickness that is greater than a single diamond crystal layer is.

The composite material makes excellent use of an abrasive, cutting tool, nozzle, or any another, wear-resistant component.

The invention will now be explained in more detail with reference to examples, in which in the following manner, if nothing else is indicated, the procedure was:

Silicon carbide substrate

A hexagonal powder was used as the pressure-transmitting medium Boron nitride with a fine particle size of about 2 to about 20 micrometers is used.

The polycrystalline silicon carbide substrate was in the form of a disk with a thickness of about 5.05 mm.

A device was used which essentially corresponded to the device shown in FIGS.

909817/0942

The "filling material used in the device according to FIG. 4 was at room temperature up to a pressure of 5600 kp /

cm cold pressed.

The amount of door alloy available was sufficient to completely soak the compressed diamond mass and the contact area of the substrate to wet and fill the pores of the interface.

The impregnation alloy was a silicon-rich, a eutectic containing alloy.

The density of the polycrystalline silicon carbide body used as the substrate is a fraction the theoretical density of silicon carbide of 3.21 g / cm.

All sintered and hot-pressed, polycrystalline silicon carbide bodies used as substrates had im essentially the same composition. The silicon carbide bodies contained silicon carbide, about 1 to 2 percent by weight Boron based on silicon carbide and less than about 1 weight percent elemental, submicron lying carbon based on silicon carbide. The carbon was in the form of small particles before, the size of which was in the submicron range. That used Diamond powder had a particle size of 1 to about 60 micrometers, with at least 40 percent by weight of the Diamond powders had a particle size of less than 10 micrometers.

A diamond density, given in percent by volume of the diamond body, was determined using the standardized point counting technique determined using a photomicrograph of a polished surface magnified 690 times and

909817/0942

the surface area analyzed had a size that sufficient to represent the microstructure of the entire body.

The information on diamond density, which is in the range of over 70 percent by volume, but below 90 percent by volume on the volume of the polycrystalline diamond body are based on experience and results with similar experiments and particularly to experiments in which the polycrystalline diamond body was made alone. The information about the appearance of the whole, glued-on polycrystalline body and also the information on the volume of the formed, cleaned polycrystalline diamond body of the composite material compared to the volume of the originally used Diamond powders are based on the assumption that less than 5 percent by volume of the diamond powder in non-diamond-shaped, elemental carbon have been converted.

Examples 1 to j?

In the examples 1 to 5 compiled in Table I, a molybdenum cup was used which was equipped with a Zirconium sleeve was lined. A cast alloy disc with the specified composition and thickness and with a diameter substantially corresponding to the zirconium sleeve was within the Zirconium sleeve placed on the bottom of the cup. The diamond powder was poured over the disk in the specified amount packed. Finally, the specified, polycrystalline silicon carbide disk was placed on top of the diamond powder, so that the bowl was closed at the top with a stopper Ή, like this in Pig. 2 is shown.

The well provided with the stopper was then in the

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in the manner shown in Fig. 4 into a powder of hexagonal Packed up boron nitride. All of the batch was placed in a steel mold at room temperature to a pressure of about 5600 kp / cm ~ cold-pressed, with the contents on the bowl an essentially isostatic pressure was applied. The pressure was maintained until the pressure with the formation of a dimensionally stable shaped body, i.e. an essentially isostatic system of the powder-enclosed container. From previous experiments it was known that the density of diamond crystals in the compressed arrangement, i.e. in the one in the form of a molded body, which is essentially isostatic System of the powder-enclosed cup closed with a stopper, more than 75 percent by volume of the compressed Diamond mass was.

The compressed assembly 21 of the powder-enclosed cup closed with a stopper was made then hot pressed. The assembly 21 was placed in a graphite mold which is the same diameter as the steel die as shown in FIG. The graphite mold was placed in an induction furnace. Of the The interior of the cup closed by the stopper was first evacuated, and then with a nitrogen atmosphere filled by evacuating the induction furnace to a pressure of approximately 10 torr and then filling with nitrogen became. On the surface in the graphite mold

Order 21 a pressure of about 350 kp / cm was then applied and maintain it. The graphite mold with the arrangement 21 was then in about 5 to 7 minutes on the indicated, maximum hot-pressing temperature heated by the induction furnace. When the arrangement was heated up, the pressure rose due to the Thermal expansion of the system to the specified maximum hot pressing pressure.

909817/0942

At the specified temperature at which the penetration begins or continues, the pressure drops to about 350 kgf / cm ~. This pressure drop indicates this indicated that the alloy had become liquid and had begun to penetrate the compressed diamond mass. The pressure was then increased again to the specified maximum hot-pressing pressure and for one minute at the specified maximum hot-pressing temperature kept at this maximum hot-pressing pressure to ensure complete penetration the alloy in the small capillaries of the compressed diamond mass. The heater was on then switched off, but no additional pressure applied. This made for a high pressure at a high temperature, but for a reduced pressure at low temperature, so that sufficient geometric stability was achieved and the hot-pressed arrangement its dimensions held until it was cooled to a temperature sufficient for handling.

The composite material was finally obtained by removing the surrounding metal, i.e. the molybdenum cup and the Zirconium bushing as well as the excess alloy on the outer surfaces of the composite material by grinding and Sandblasting has been removed.

The resulting one-piece, purified composite bodies were in the shape of a substantially uniform Disc, which in Examples 1 to 3 a thickness of approximately 5 mm and in Example 4 a thickness of approximately 4 mm.

Examples 6 and 7

In Examples 6 and 7 compiled in Table I, no metallic container, no lining

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sleeve or substrate used. The device used, however, essentially corresponded to that in FIGS. 4 and 5? ^Θ ~ showed device. In Examples 6 and 7, the hexagonal boron nitride powder was packed in the die shown in Fig. 4, and a cylinder used as a mold was printed in the powder. The cylinder was made of cemented metal carbide and was about 9 mm in diameter and about 6.3 mm in thickness. The axis of the cylinder was roughly aligned with the central axis of the die.

After the cylinder was inserted into the powder, more hexagonal boron nitride powder was made into the die · - · given until the cylinder is completely covered was. The powder-enclosed cylinder was at

Room temperature pressed under a pressure of 3500 kp / cm. The punch 23 a was then withdrawn and the punch 23 was pressed to partially eject the Powder-enclosed cylinder from the die used.

The free part of the pressed powder was removed, exposing part of the cylinder. The cylinder was then pulled out, leaving a cavity that had been forced into the powder by the cylinder. Both Examples 6 and 7 were made of a cast alloy disc with the specified composition and Thickness and placed with a diameter corresponding to the inner diameter of the cavity on the bottom of the cavity. A layer of diamond powder with the indicated particle size, amount and thickness was above packed on the alloy disc.

A disk made of hot-pressed powder made of hexagonal boron nitride and serving as a stopper with an inner diameter The cavity's roughly equivalent diameter was placed inside the cavity on top of the diamond powder

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laid to ensure that the surface of the resulting polycrystalline diamond body becomes flat.

The entire mass was then pressed into the center of the die by the punch 23 a. The stamp 23 a was then withdrawn. Then another powder was made of hexagonal Put boron nitride into the die until the hot-pressed disk made of hexagonal boron nitride is covered, so that the cavity or the cavity with contents is enclosed by the hexagonal boron nitride, as shown in FIG. 4 is. The feed was then at room temperature

2 cold-pressed in the steel die under a pressure of 5600 kgf / cm, as shown in FIG. 4, the cavity with contents being subjected to a substantially isostatic pressure. The pressing pressure was maintained until it had stabilized with the formation of a dimensionally stable shaped body, ie an essentially isostatic system of the powder-enclosed cavity with its contents. It was known from earlier experiments that the compressed diamond mass in the essentially isostatic system of the powder-enclosed cavity with its content, which is present as a shaped body, has a diamond density of over 75 percent by volume.

The compressed arrangement of the powder-enclosed cavity essentially corresponded to the arrangement 21 except that no metal container was used. The resulting pressed arrangement was then hot pressed and for this purpose in a graphite shape shown in Fig. 5 with the same diameter as the Steel die pressed in. The graphite mold was then placed in an induction furnace. The interior of the cavity was first evacuated and then filled with a nitrogen atmosphere by initially using the induction furnace evacuated to a pressure of about 10 Torr and

909817/0942

schliessetfd was filled with dry nitrogen. On the The arrangement located in the graphite form became a print

ο
of about 350 kp / cm exerted and maintained. The pressurized assembly was then inductively heated to the specified maximum hot-pressing temperature in about 5 to 7 minutes. When the arrangement was heated up, the pressure rose to the specified maximum hot-pressing pressure due to the thermal expansion of the entire system.

At the specified temperature at which the impregnation started, the pressure dropped to about 350 kgf / cm ". This A drop in pressure indicates that the specified alloy has melted, become liquid, and into the diamond mass had penetrated. The pressure was then increased again to the specified maximum hot-pressing pressure and a Maintained at this pressure value for a minute at the specified maximum hot-pressing temperature in order to achieve a complete Ensure penetration of the alloy into the smaller capillaries of the compressed diamond mass. the The heating was then turned off, but no additional pressure was applied. This made for a high Pressure at high temperature and for reduced pressure at low temperature, creating a sufficient geometric Stability was achieved. The polycrystalline diamond body was removed at room temperature. The ■ sealing plug did not adhere to the diamond body. After removing flakes on the surface of the diamond body adhering hexagonal boron nitride powder and excess alloy by grinding and sandblasting the one-piece, polycrystalline diamond body had the shape of a disk with the specified thickness.

In Table I, the hot-pressing temperature at which the impregnation begins is the temperature at which the Alloy is volatile and begins to penetrate into the compressed diamond mass. The specified maximum hot

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pressing temperature and the specified maximum hot pressing pressure were held simultaneously for one minute to completely fill the smaller capillaries the compressed diamond crystal mass.

Those given in Table I for Examples 6 and 7 X-ray analysis was performed on the crushed polycrystalline diamond body.

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TABLE I.

example

Potions
legie
run R lot
in (mg) approx.
Micke
in mm Diamond powder approx.
Powder-
thick in
mm Metal container
so far
available Substrate or
Plug max hot
press
pressure in Hot press
temperature
in ^D 0 226 1 lot
in mg 1.65 Mo bowl with
Zr lining hot pressed
tes SiO sub
strat (<- $ 98
Density) kp / cm Start d. Max.
Soaking Tempe
rature Atom i>
95 Si
5 Re 259 1 3oo 1.65 as in Bei
game 1) sintered
SiC substrate
("- 95 i ° you
te) 77o 1325 1375 85 Si
15 Or 323 1 3oo 1.65 as in Bei
game 1) as in Bei ^ »
game 2) 77o 1275 1375 9o Si
10 pt 23o 1 3oo o _t 76 as in Bei
game 1) as in Bei
game 2) 88o I.
OI
1375 1.52, ^r " 86 Si
14 Ti 318 1 14o 1.57 as in Bei
game 1) as in Bei
game 2) 77o 1275 1375 79 Si
21 Rh 26o 1 28o 1.4 none Stopper from he:
pressed, hexj
nalem Bornitric
powder 88o 95o "Uno 95 Si
5 RE 21 ο 1 25o 1.4 none as in example 6 LSS-
3gO-
3-
91 ο K)
OO
1390 5; ¹⁴⁹⁵ 86 Si
14 Ti 25o 91 ο OO
1345 <** i54o

example

Melting point of the impregnating alloy
in the literature in ⁰ C

TABLE I (continued) Polycrystalline Diamond Body

approx. Thickness in mm

properties

X-ray analysis of the polycrystalline diamond body

co

(D

(125o)

predicted
(Si, re binary)

1335
(Si, Or binary)

135ο
(Si ₁ Pt binary)

133o
(Si ₁ Ti binary)

(125o)
predicted

133o

1.73 1.78 1.78

0.89

1.52

1.52

The diaphragm body of the composite material appeared well saturated and well bound

as in example 1)

as in example 1)

as in example 1) as in example 1)

Pore-free, hard and extremely abrasion-resistant, as if there was no abrasion irradiation with silicon carbide particles was detected

well saturated and well bound

(cleaned area of the diamond body of the composite material)
Diamond and SiC

(cleaned area of the diamond body of the composite material)
DiamantjSi and SiC

(cleaned area of the diamond body of the composite material)
Di-amant, PtSi and SiC

("crushed, poly crystalline
Diamond body)
Diamond, SiC, ReSi ₂ and traces of Si

(crushed, polycrystalline
Diamond body,)
Diamant.SiC and

The invention will now be explained in more detail with reference to Table I. Not a single composite pane according to the examples 1 to 5 could be the interface between the polycrystalline diamond body and the silicon carbide substrate to be established. Each composite body had a continuous structure over its thickness and the diamond part was different by the grain size of the substrate. The outer surface of each polycrystalline diamond body was from Well saturated binder. The binder was evenly distributed. The individual diamond bodies were fine with each other tied together.

The polycrystalline diamond bodies of the composite materials according to Examples 1 to 4 had a diamond density which over 7o percent by volume, but below 9o percent by volume des Volume of the polycrystalline body was.

The diamond surface of the composite body according to Example 5 was polished on a cast iron block. Examination of the polished surface did not reveal any broken diamond particles holes to be traced back to light. This suggests that there is a very strong bond. the The density of the diamond crystals was about 73 volume percent based on the volume of the polycrystalline diamond body .

The polycrystalline diamond bodies according to Examples 6 and 7 were well saturated and firmly bonded. Everyone Disc-shaped polycrystalline diamond bodies were essentially made using a hammer and a wedge broken in half and the fracture surfaces were optically under a microscope at 100x magnification examined. Examination of the fracture surfaces showed that the fracture surfaces were free of pores and that the binder was uniform was distributed in the body and the fracture surfaces trsns-

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were granular and not intergranular. This shows that the break is across the crystals and not along the crystal faces proceeded. This indicates that the bond produced by the binder is extremely good and just as strong like the diamond crystal itself is.

The diamond density of the disk according to Example 6 was above 70, but below 90 percent by volume of the body.

A fracture surface of the disk according to Example 7 was found polished on a cast iron block. Examination of the polished surface did not reveal any evidence of broken diamond particles Holes are revealed, suggesting that there is a very strong bond. The density of the diamond crystals was about 80 percent by volume of the polycrystalline diamond body.

Example p

The composite material produced according to Example 1 was used as a cutting tool. The free area of the polycrystalline diamond body of the composite material was with ground smooth with a diamond grinding wheel and provided with a sharp cutting edge. The substrate of the composite material was then clamped in a tool holder.

Part of the cutting edge was examined on a lathe with which a Jackfork sandstone was fed with a feed of 0.13 mm per revolution and a cutting depth of 0.5 mm.

At a cutting speed of about 30 m per minute measured on the surface, the wear was included 1.26 x 1o cnr per minute. Another part of the cutting edge

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was at a cutting speed measured on the surface examined from 84 m per minute. The wear and tear was

-6 ο

at 8.6 χ 10 cm per minute. Another part of the cutting edge was examined at a cutting speed of 88.4 m per minute measured on the surface. The wear in this case was 24 cur ⁵ χ 10 per minute.

The composite was removed from the tool holder. An examination of the interface between the diamond body and the substrate showed that these machining attempts had no effect on the interface.

Example 9

The same procedure as in Example 8 was followed, except that the composite body according to Example 2 was used.

A portion of a cutting edge was measured at the surface at a cutting speed of 33.5 m Pi O ¹ minute a wear of 3.32 χ Λ ο ~ cm per minute. Another part of the cutting edge had a wear of 24.3 × 10 cm per minute at a cutting speed of 97.5 m per minute measured on the surface.

An examination of the composite body after machining showed that these machining attempts did not Had an influence on the interface between the polycrystalline diamond body and the silicon carbide substrate.

Example 1o

The procedure was as in Example 8 with the exception

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that the "composite material according to Example 3 was used

Part of one cutting edge had on one

Surface measured cutting speed of 33.5 m above sea level

-6 '6 minute wear of 3.8 χ 1o cm per minute. Another part of the cutting edge, at a cutting speed of 97.5 m per minute measured on the surface, had a wear of 3o.3 χ 10 cm "per minute.

An examination of the composite material after machining showed that these machining trials does not affect the interface between the polycrystalline diamond body and the silicon carbide substrate had.

Example 11

The procedure was as in Example 8 with the exception that the composite material according to Example 4 was used.

After 4 minutes of successful cutting with a cutting speed of 30 m measured on the surface per minute small pieces broke out of the cutting edge. Another part of the cutting edge broke after 6 minutes successful cutting with a cutting speed of 85 m per minute measured on the surface Pieces from the cutting edge. It is assumed that the breaking out of the cutting edge occurs at hot-pressing temperatures that were not high enough to get the liquid, silicon-rich alloy into the small capillaries the pdycrystalline diamond mass during the hot pressing process to wash in. A comparison with Example 7 of Table I shows that the higher hot-pressing temperatures produce a well-soaked and tightly bound polycrystalline Diamond bodies.

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Example 12

In the production of the composite material, the procedure was essentially as in Example 2 with the exception that 260 mg of the silicon chromium alloy was used and the alloy disc was 1.3 mm thick.

There are also 250 mg of the diamond powder used, with 60 $> a grain size 53-62 microns, 30 wt.% Wt. I "had a particle size of 8-22 microns and 1o wt. A particle size of from 1 to about 5 microns. The diamond powder was packed to a thickness of about 1.4 mm. A zirconium cup with a zirconium lining was also used.

The maximum hot press pressure was about 910 kp / cm and the hot-pressing temperature ranged from about 1250 C at the beginning of the penetration of the liquid, silicon-rich alloy into the pressed diamond crystal mass up to a maximum hot-pressing temperature of about 1500 C. The composite material was obtained in the same manner as in Example 2. The composite material was substantially in the shape of a uniform disc with a thickness of about 1.5 mm.

The silicon carbide substrate was ground away from the composite material and the polycrystalline diamond body was subjected to a thermal stability test. The substrate was heated in air to a temperature of 90O ⁰ C, which represented the limit temperature of the furnace. During heating was measured the linear thermal expansion coefficient for temperatures of 10O ⁰ C and 90O ⁰ C. The furnace was switched off at 90O ^{0 C.}

The experimental data and the examination of the sample, i.

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of the polycrystalline diamond body after the test showed that there was no sudden change in length in the sample during the entire heating process. There was no evidence for _c a constant, caused by the heating loss of the sample.

Example 13

The procedure was essentially as in Example 2 with the exception that a silicon wafer in one Zirconium bowl with a zirconium lining was used, to form a silicon-rich zirconium alloy in situ.

6 composite materials were made. For the preparation of 3 composite materials, a diamond powder was used in which 60 wt. $ A grain size 53-62 microns, 30 wt. $> A grain size 8-22 Mikromaber and 10 wt. $ A particle size of from 1 to about 5 Mikromaber had . The three other composites were made using a diamond powder that had a grain size of 1 to 60 microns, with at least 40% by weight having a grain size of less than 10 microns.

The maximum hot-pressing pressure was about 910 kgf / cm ^ and the hot-pressing temperature ranged from etwa1340 ⁰ C up to a maximum hot pressing temperature of about 150o ⁰ G. The lying at the lower end of the specified temperature range temperature of from about 134O ⁰ C is the temperature at which the The impregnation process begins and it becomes clear that the silicon-rich zirconium alloy was formed in situ and has become liquid.

Each composite material was obtained in substantially the same manner as in Example 2. Each composite

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6Ί -

material was in the shape of a disk.

The surface on the front and cylinder surfaces of the polycrystalline diamond body of all 6 composite materials was sanded. The difficulty of grinding these composite materials with a diamond grinding wheel demonstrated that the abrasion resistance of these diamond bodies with the was comparable to commercially available polycrystalline diamond products.

The 3 composite materials made from diamond powder with a grain size of 1 to 60 micrometers had insufficiently mixed aggregates of diamond powder with a grain size of less than 2 micrometers. An examination of the ground edges of the polycrystalline body showed that these aggregates were incomplete were impregnated with the alloy. However, the rest of the cut diamond area was well bonded.

An optical examination of the composite materials left no noticeable defects or mutually offset, different intermediate layers between the silicon carbide substrate and recognize the diamond layer. Four composite materials were broken to reveal the internal structure. When the fracture surfaces were visually examined, no visible intermediate layers or defects were found on the Interface between the silicon carbide substrate and the polycrystalline diamond layer was found.

The continuity of the structure at the interface between substrate and diamond layer was excellent and only that different grain sizes of the diamonds and the silicon carbide read the interface between the substrate and the Determine the diamond layer.

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Two of the composite materials were tested as cutting tools on a lathe, with which a rod-shaped, A sand-smoothed whetstone that has a strong abrasive effect has been turned off. It was made with a depth of cut of 0.76 mm, a "feed rate of 0.13 mm per revolution and a cutting speed of 183 m per minute measured on the surface. After a cutting time of For 16 minutes and 22 seconds, the front cutting edge of the two tools showed an even abrasion of about 0.13 mm. This shows that the cutting edge is excellent Had abrasion resistance.

Example 14

The composite material produced according to Example 1 was essentially broken in half with a hammer and wedge. The fracture surfaces were under examined optically with a microscope with a magnification of 100 times. Examination of the fracture surfaces showed that Both the polycrystalline diamond body and the interface of the composite material were pore-free, the binder evenly distributed in the diamond body and the fracture was transgranular and not intergranular, i.e. that the The fracture was across the crystals and not along the crystal faces. This suggests that the Binder causes bonding very well and is just as strong as the diamond crystals themselves. They weren't visible either Interlayers or defects at the interface between the silicon carbide substrate and the attached polycrystalline Determine the diamond layer. The fracture surface of the composite material had a continuous structure and only the different one Grain size between the diamond and the firmly adhering substrate lieas the boundary between the substrate and recognize the attached polycrystalline diamond body.

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The fracture surface of the composite material was polished. An optical examination of the polished fracture surface shown in FIG. 7 did not reveal any broken diamond particles holes to be traced back to light. This shows that there is a very strong bond. Fig. 7 shows in their upper part the polycrystalline diamond body and in its lower part the substrate. The area in between can be identified by the different crystal structure between the diamond body and the substrate. The concentration the diamond crystal was about 7 * 1 volume percent of that of the polycrystalline Diamond body in the sample shown in FIG.

Silicon nitride substrate

A fine-grained medium was used as the pressure-transmitting medium Hexagonal boron nitride powder with a grain size of about 2 to about 20 micrometers is used.

The polycrystalline silicon nitride substrate was in the form of a disk, which in Examples 2 and 3 had a thickness of about 3.18 mm and in Examples 5 and 6 a thickness of about 2.5 mm. The polycrystalline silicon nitride substrate was a commercially available hot-pressed material that had a density of over 99 # »that is, nearly a density of 100 $> . Based on the weight of the hot-pressed silicon nitride body, the material contained 1/2 # MgO, about 1/2 $> Pe, about 1/200 $> metallic impurities such as Ca, Al, and Or, 2 # free Si, 1 f SiO and silicon nitride as the remainder.

The device used corresponded essentially to the device shown in FIGS.

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The feed was as shown in FIG. 4 at room temperature

Cold pressed up to about 5600 kp / cm. The density of the diamond crystals in the compressed configuration was over 75 percent by volume of the compressed diamond mass.

The amount of impregnating alloy was sufficient, the compressed one To completely soak the diamond mass and to wet the contact surface of the Sdstrats and the pores of the Fill the interface.

The impregnating alloy was a silicon-rich alloy containing a eutectic.

The density given here of the polycrystalline silicon nitride body used as the substrate is the fraction density of the theoretical density of the silicon nitride of 3.18 g / cm ³ .

The composite material or the polycrystalline diamond body was broken apart with the aid of a hammer and a wedge .

The optical examination of the fracture points was carried out under a microscope at a magnification of about 100 times.

The fracture surface of the polycrystalline body was polished on a cast iron block.

Each given in percent by volume of the body Diamond density was determined according to the standardized point counting technique, using a photomicrograph of the polished cross-sectional area magnified 690 times and the The surface area analyzed had a size which adequately represented the microstructure of the entire body.

909817/0 9 4?

The information about the diamond density, which is in the range of over 70 »but below 9o percent by volume based on the volume of the polycrystalline body are based on experience and similar experiments, in particular on experiments in which the polycrystalline diamond body alone was produced. The appearance of the polycrystalline body as The whole and also the volume of the recovered, purified polycrystalline diamond body of the composite material in comparison to the volume of the originally used diamond powder are based on the assumption that less than 5 percent by volume of the Diamond powder in non-diamond-shaped, elemental carbon have been converted.

In Examples 15 and 16 the one was high in silicon Impregnation alloy an in situ formed alloy of silicon and zirconium.

Example I5

In this example, a polycrystalline diamond body was produced without a substrate.

A cast silicon wafer weighing 1 mg was placed inside a zirconium can in a molybdenum cup arranged. About 5OO mg of fine diamond powder, its Grain size was in the range from about 1 to about 60 micrometers and of which at least 40 wt. $ A grain size of below 10 micrometers was packed on top of the silicon wafer. A molybdenum bowl with a slightly larger diameter when the original bowl filled with silicon and diamonds was used as a lid over the opening of the original bowl filled with silicon and diamonds.

The container thus formed was then made according to

909817/0942

Fig. 4 packed in a powder of hexagonal boron nitride. The entire batch was cold in a steel die at room temperature to a pressure of about 5600 kgf / cn pressed, with an essentially isostatic, i.e. one from all directions, on the container and the contents essentially uniform pressure was exerted. The pressure was maintained until the pressure increases with the formation of a dimensionally stable molded body, i.e. an essentially isostatic system of the powder-enclosed container had stabilized. From previous experiments it was known that the compressed Diamond mass in the system present as a shaped body has a diamond density of over 75 percent by volume based on the volume the compressed diamond mass. The silicon was in an amount of about 80 percent by volume of that compressed Diamond mass present.

The resulting, compressed arrangement 21 of the container enclosed by the powder was then hot-pressed. For this purpose, the arrangement 21 was inserted in the manner shown in FIG. 5 in a graphite mold which had the same diameter as the steel die. The graphite mold was placed in an induction furnace. The interior of the container was first evacuated and then filled with a nitrogen atmosphere by first evacuating the induction furnace to about 10 Torr and then filling it with nitrogen. A pressure of approximately kp / cm was then exerted and maintained on the assembly 21 located in the graphite mold. The pressurized assembly 21 was then inductively heated to a temperature of 150 ° C. in 7 minutes. When the arrangement was heated up, the pressure rose to around 700 kgf / cm due to the thermal expansion of the system. After reaching a temperature of about 135O ⁰ G, the pressure fell to about 350 kp / cm ² . This pressure drop suggests that silicon-rich zirconium

909817/0942

alloy had formed, had become liquid and had begun to penetrate the compressed diamond mass. The pressure was increased to the maximum hot press pressure of 700 kp / cm. Had been than the temperature of I5OO ⁰ C is reached, the assembly was held for one minute at the maximum hot pressing temperature of 150o ⁰ C under the pressure of 700 kp / cm to achieve complete saturation of the smaller capillaries to provide the compressed diamond mass. The heating was then turned off, but no additional pressure was applied. In this way, a high pressure at a high temperature, but a reduced pressure at a low temperature and thus sufficient geometric stability was ensured. The hot-pressed assembly thus retained its dimensions until it was cooled to a temperature sufficient for handling.

The resulting polycrystalline diamond body was obtained by removing the cladding metal, i.e. the molybdenum bowl and the zirconium sleeve and excess silicon on the outer surfaces of the body by grinding and sandblasting removed.

The resulting, one-piece polycrystalline diamond body was in the form of a disk with a thickness of about 3 mm. The diamond body appeared to be well saturated and have a firm bond ku.

X-ray diffraction analysis of the cleaned surface, through which the alloy penetrated shows that the body is composed of diamond, silicon carbide and elemental silicon and silicon carbide and elemental silicon are present in an amount of at least 2 percent by volume of the body was. In the X-ray diffraction analysis, however, no non-diamond-shaped, elemental carbon fixed

909817/094?

will be presented.

An examination of the fracture points of the disc showed that the fracture surface was transgranular and not intergranular was, that is, the fracture surface ran across the crystals and not along the crystal surfaces. This indicates indicates that the bond created by the binder is very good and as strong as the diamond crystals themselves.

When examining the fracture surfaces, it was found that the fracture surfaces were free of pores, and so was the binder was evenly distributed over the body.

When examining the polished fracture surface it was found that the polished surface had no holes attributable to broken diamond particles, which is evident indicates that there is a strong bond and the diamond body is suitable as an abrasive.

The density of the diamond crystals was about 81 volume percent of the polycrystalline diamond body.

A photomicrograph of the polished surface magnified 690 times showed a white phase. In an X-ray spectral analysis this phase it turned out that the phase consisted of zirconium and silicon, what on it indicates that this phase was zirconium silicide.

Example 16

In this example, the composite material was made using a hot-pressed, polycrystalline silicon nitride manufactured as a substrate.

909817/094?

A cast silicon wafer weighing 142 mg was placed inside a zirconium sleeve in a zirconium cup. 270 mg of diamond powder with a layer thickness of about 1.5 mm were applied to the silicon wafer. The diamond powder contained 85 wt. $> Diamond particles having a particle size from 53 to 62 microns, and 15 wt.% Diamond particles having a grain size of about 5 microns. Instead of the metal cover used in Example 1, a plug 14, shown in FIG. 2, made of hot-pressed, polycrystalline silicon nitride was used.

The closed bowl was then made according to J ¹ Xg. 4 packed in a powder of hexagonal boron nitride. The entire charge was cold pressed at room temperature in the manner described in Example 1, with the sealed cup and its contents being subjected to essentially isostatic pressure. The pressing pressure was maintained until the pressure had stabilized with the formation of a dimensionally stable shaped body, ie an essentially isostatic system of the cup enclosed with powder. The density of the diamond crystals was over 75 percent by volume of the compressed diamond mass. The resulting, compressed arrangement 21 of the powder-coated, sealed cup was then hot-pressed in the same way as in Example I5 with the exception of the information contained in Table II.

The resulting composite material was obtained by that the cladding metal and excess silicon on the outer surfaces of the composite material by grinding and sandblasting was removed.

Examples I5 and 16 are summarized in Table II. Also in the examples shown in Table II 17 »19 and 2o a cast alloy was in the form of a disc

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with the specified composition and thickness as well as with a diameter corresponding to the specified lining Diameter arranged within the sleeve-like lining on the bottom of the specified cup. The diamond powder was packed in the specified amount on top of the disk. Eventually the stated became polycrystalline Silicon nitride substrate deposited on top of the diamond powder. The silicon nitride substrate formed a cup sealing Stopper that is in Pig. 2 is provided with the reference number 14. The sealed bowl was then used in the method described in Example 2 described way with the exception of the information contained in Table II cold and hot pressed. The resulting composite material was obtained in substantially the same manner as in Example 16.

The resulting, cleaned, one-piece composite material of Examples 16, 17, 19 and 20 was substantially in the form of a uniform disc, which in Examples 16 and 17 has a thickness of about 4.7 mm and in Examples 19 and 2o was about 3.8 mm thick.

In Example 18, a polycrystalline diamond body was made without the use of a metallic container, a liner or substrate. However, the devices used were essentially the same the devices shown in Figs. The hexagonal boron nitride powder was incorporated into the die of FIG packed. A cylinder serving as a mold was pressed into the powder. The cylinder was made of cemented metal carbide and was about 8.9 mm in diameter and about 6.3 mm in thickness. The axis of the cylinder was essentially aligned with the central axis of the die.

After inserting the cylinder into the powder, additional, powdery hexagonal boron nitride into the die

909817 / 09A2

given to completely cover the cylinder. The from Powder-enclosed cylinders were pressed at room temperature under a pressure of 350 kgf / cm. The press die 23 a was then pulled out and the ram 23 was used to partially push out the cylinder surrounded by powder from the die.

The exposed portion of the pressed powder was removed to partially expose the cylinder. The cylinder was then pulled out, leaving a cavity pressed in by the cylinder. In Example 4, one became off a cast alloy disc with the specified composition and thickness as well as with an inner diameter of the cavity substantially corresponding diameter arranged on the bottom of the cavity. One layer off Diamond powder with the specified grain size, the specified amount and the specified thickness was packed on top of the alloy disc. A disc of hot-pressed, powdery, Hexagonal boron nitride with a diameter corresponding to the inner diameter of the recess was used in the Recess placed on top of the diamond powder. The hot-pressed disc served as a plug to ensure that the surface of the resulting polycrystalline diamond body is flat.

The entire mass was then pressed into the center of the die with the aid of the press ram 23 a, whereupon the press ram 23 a was withdrawn. An additional amount of powdered hexagonal boron nitride was put into the die given to cover the hot-pressed disk made of hexagonal boron nitride and the recess and its contents in the 4 to be completely enclosed with hexagonal boron nitride as can be seen. The resulting load was then cold-pressed at room temperature in the steel die under a pressure of 5600 kp / cm in the V / eise shown in Fig. 4,

909817/094 /

the recess and its contents being essentially isostatic Have been subjected to pressure. The pressing pressure was maintained until the pressing pressure was formed a dimensionally stable shaped body, i.e. an essentially isostatic system of the powder-coated The recess and its contents had stabilized. From previous experiments it was known that the diamond crystals in the as Shaped body present, essentially isostatic system of the powder-coated recess with content a density of over 75 percent by volume of the compressed diamond mass.

The resulting, pressed arrangement of the powder-coated recess and its contents essentially correspond of the pressed assembly 21 except that no metal container was used. The resulting, pressed The assembly was then hot pressed, i.e. placed in the graphite mold shown in Fig. 5, which is the same diameter like the steel die had. The graphite mold was then placed in an induction furnace. The interior of the The recess was first evacuated and then with a nitrogen atmosphere by first evacuating the furnace to about 10 Torr and then again with dry Nitrogen was added. On those in the graphite form

The assembly located was then a pressure of about 35o kp / cm exercised and maintained. The pressurized assembly was then in about 5 to 7 minutes to the indicated, maximum hot-pressing temperature heated. When the assembly was heated up, the pressure increased due to the thermal expansion of the entire system to the specified, maximum hot-pressing pressure.

At the specified temperature at which the impregnation began, the pressure dropped to about 350 kp / cm. This pressure drop indicates that the specified alloy

909817/094?

melted and liquefied and began to penetrate the diamond mass. The pressure was then again increased to the specified maximum hot-pressing pressure and for one minute at the specified maximum hot-pressing temperature held to ensure complete penetration of the alloy into the smaller capillaries of the compressed diamond mass to ensure. The heating was then turned off, but no further pressure was applied. This created a lot of pressure at high temperature, but for a reduced pressure at low temperature and thus for a sufficient, geometric Stability. The resulting polycrystalline diamond body was taken out at room temperature. The sealing plug did not adhere to the diamond body. Wake up removing flakes on the surface of the polycrystalline Hexagonal boron nitride powder adhering to diamond bodies and excess alloy by grinding and sandblasting had the one-piece, polycrystalline diamond body the shape of a disc with the specified thickness.

The hot-pressing temperature given in Table II at which the impregnation process begins is the temperature at which the alloy is liquid and begins to penetrate the compressed diamond mass. the The specified maximum hot-pressing temperature and the specified maximum hot-pressing pressure were simultaneously for one minute maintained to completely fill the smaller capillaries of the compressed diamond crystal mass to ensure.

909817/0942

at Impregnation alloy lot
in mg approx.
thickness
in mm Table II approx.
powder
thickness
in mm Metal container Substrate or game Atom $> 330 Diamond powder (as far as available
the) Plug 15th poured
nes Sili
cium 142 0.76 Grain size quantity
in micrometers- in mg
ter 1.5 Mo bowl with
Zr lining no, Mo bowl
as a lid 16 poured
nes Sili
cium 260 1 1 to 6o where
of 40 wt. fo
less than 1o 500 1.6 Zr bowl with
Zr clothing hot pressed
tes silicon
nitride 17th 85 Si
ΪΪ5 Cr 210 1 82 wt.% With
53 to 62, 15
Gew. ^ With / v5 270 1.4 Mo bowl with
Zr lining hot pressed
tes silicon
nitride 8606 18th 86 Si
14 Ti 133 0.76 like example
1) 290 none hot pressed
tes, hexagona- ^
les boron nitride,
powder —I
-4
^ «,
O
to 19th 86 Si
14 Ti 121 like example
1) 250 Mo bowl with
Mo lining hot pressed
tes, silicon
nitride 20th 95 Si
5 Re like example
1) 227 Mo bowl with
Mo lining hot pressed
tes silicon
nitride 7o wt. ^ With
1 to 60, of which
17 wt. ^ With 1
to 10, and 3o
Weight fo with 1 to
5,200

Maximum
Hot press
pressure in
kp / cm
C ° Table II 1500 (Port setting) Pollycrystalline
Diamond body
approx. X-ray
Thickness in analysis of the slide
mm shell (cleaned area)
Diamond, SiO and
Si at
game 700 Hot-pressing temperature
Impregnation maximum
temperature 1525 2.9 15th 910 1350 1450 1.5 16 770 ~ 1300 1540 1.4 (broken body
per) diamond vn
SiC and TiSi ₂ , 17th 910 1240 1525 1.5 18th 910 1345 1540 1.3 19th 910 1322 1.1 20th 1340 Melting point
the potion
ying in
literature 1360
(Si-9.6 wt. #
Zr eutectic) 1360
(Si-9.6 wt. #
Zr eutectic) 1335
(SiGr binary) 1330 1330 1250
(predicted)

CJI OO CO

Examples 16, 17, 19 and 20 show the preparation of the composite material according to the invention. Compartment, one optical Investigation found that each composite material in these examples had a continuous structure, but the Interface between the diamond body and the substrate due to the different grain size and due to Color differences between the diamond body and the substrate could be determined. The silicon nitride substrate was darker than the gray diamond body. The outer surface of a each polycrystalline diamond body was well saturated, the binder being evenly distributed. The diamonds were well connected.

The polycrystalline diamond body of the composite materials according to Examples 17 and 18 had a diamond density that over 7o percent by volume, but below 9o percent by volume des Volume of the polycrystalline body was.

The diamond surface of the composite material according to the example was polished. When examining the polished It was found that the polished surface had no holes due to broken diamond parts possessed, suggesting that there is a strong bond. The density of the diamond crystals was about 71 volume percent of the polycrystalline diamond body according to the example

The ροIy crystalline diamond body in Example 18 was a well soaked, tightly bound, hard disk. The diamond body was essentially broken in half. During the optical examination of the fracture surfaces it was found that the fracture surfaces were free of pores the binder was evenly distributed in the diamond body and the fracture was transgranular and not intergranular means that the break ran across the crystals and not along the crystal boundaries. This indicates

909817/0942

that the binding brought about by the binder is very good and as solid as the diamond crystals themselves.

A broken surface of the disc of Example 18 was polished. Upon examination of the polished surface was found that the polished surface did not have any chipped on Had holes attributable to diamond particles, confirming the strong bond. The density of the diamond crystals in the diamond body of Example 18 was about 80 volume percent of the polycrystalline diamond body.

Example 21

The composite material according to Example 17 was used as a cutting tool. The free area of the polycrystalline Diamond body of the composite material was ground with a diamond grinding wheel around the free surface of the diamond body to be smoothed and provided with a sharp cutting edge. The composite substrate was then in a tool holder clamped in.

Part of the cutting edge was examined on a lathe with which a Jackfork sandstone was fed with a feed of 0.13 mm per revolution and a cutting depth of 0.5 mm was turned off.

At a cutting speed of 28.5 m per minute measured on the surface, the abrasion was 3.6 χ 1o ~ cnr per minute. Another part of the cutting edge became at a cutting speed measured on the surface examined from 79 * 3 m per minute. The abrasion in this case was 8.2 χ 10 cm per minute.

The composite material was removed from the tool holder, leaving the interface between the diamond body and the

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Substrate was examined. It turned out that the machining operations carried out had no effect on the ■ composite material had.

Example 22

The same procedure as in Example 21 was followed, with the exception that that prepared according to Example 19 was carried out Composite material was used.

Part of the cutting edge was cut at a surface cutting speed of 30.5 meters per minute examined. After a cutting time of 2 minutes, the cutting edge left a very small wear scar which indicated excellent wear resistance. The Jackfork sandstone, however, had a deep groove. Because the composite was brittle, a small piece of the cutting edge broke off.

An examination of the composite material after the cutting process showed that the cutting tests had no effect had the interface between the polycrystalline diamond body and the silicon nitride substrate.

Example 23

The composite material produced according to Example 2o was essentially broken into two halves. The fracture surfaces were examined optically. When examining the fracture surfaces it was found that both the polycrystalline Both the diamond body and the interface of the composite material were pore-free, and the binder was uniform in the diamond body distributed and the break was transgranular and not intergranular, i.e. that the break across the crystals

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and did not run along the crystal boundaries. This indicates that the caused by the binder Bond is very good and just as strong as the diamond crystals themselves. There could also be no visible intermediate layers or defects are found at the interface between the silicon nitride substrate and the polycrystalline diamond layer will. The fracture surface of the composite material had a continuous structure. Only the different ones The grain size between the diamond and the firmly adhering substrate as well as the darker color of the substrate left the Recognize the boundary between the substrate and the polycrystalline diamond body.

The fracture surfaces of the composite material were polished. In the optical examination of the polished ones shown in FIG The fracture surface was found to be that the polished surface was not due to broken diamond particles Had holes. This is an indication that there is a strong bond. Fig. 7 shows the in its upper part polycrystalline diamond body and in its lower part the substrate. The interface in between can through the different crystal structure and made up by the different color between the diamond body and the substrate will. The density of diamond crystals was about 75 volume percent of that of the polycrystalline shown in FIG Diamond body.

Example 24

The composite materials produced according to Examples 16, 17 and 19 were essentially broken in half. The fracture surfaces were examined visually. When examining the fracture surfaces, it was found that both the polycrystalline diamond body and the interface of each composite material was pore-free,

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- 8ο -

the binder is evenly distributed in the diamond body and the break was transgranular and not intergranular, i.e. that the break was across the crystals and not along the Crystal boundaries ran. This indicates that the binding caused by the binder is very good and as well solid like the diamond crystal itself. There were also no visible intermediate layers or defects at the interface between the silicon nitride substrate and the adherent polycrystalline diamond layer. the The fracture surface of each composite material had a continuous one Structure. Only the different grain size between the diamond and the firmly adhering substrate, as well the darker color of the substrate indicated the boundary between the substrate and the polycrystalline diamond body.

The fracture surface of the composite material according to Example 19 has been polished. When examining the polished fracture surface, it was found that the polished surface did not have any broken out Diamond particles had holes traced back, suggesting a strong bond. One Photomicrograph of the polished surface at a magnification of 69o showed an intermediate layer of the binder at the interface. When evaluating an electronic micrograph of the polished surface with a 1000-fold magnification an intermediate layer of binder was found at the interface, the maximum thickness of about 3 microns.

An x-ray spectral analysis of the binder in the intermediate layer and in the polycrystalline diamond body showed that the components in both cases the same were.

In summary, it can be stated that the invention relates to a method for producing a composite material

909817/0942

of a polycrystalline diamond body and a substrate in which a diamond crystal mass is in contact with a silicon-rich alloy containing a eutectic and a silicon carbide or silicon nitride ceramic substrate arranged in a container and inserted into a pressure-transmitting powder medium. The powder medium is pressurized so that an essentially isostatic pressure is exerted on the container and its contents is exercised, which is sufficient to stabilize the dimensions of the container and its contents. The present in the form of a molded body, essentially isostatic system of the powder-coated container is hot-pressed, whereby a liquid, a silicon-rich alloy containing eutectic is formed and into the spaces between the diamond crystals penetrates and wets the contact surface of the silicon carbide substrate, so that, after cooling, a firmly bonded, one-piece Composite material is created.

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Claims (17)

PATENT CLAIMS 1. A method for producing a one-piece composite material from a polycrystalline diamond body and a
Silicon carbide or silicon nitride substrate using
a hot pressing process, characterized in that a) in a container or bowl serving as a shield a solid mass of a silicon-rich alloy containing a eutectic or solid components for
Formation of a silicon-rich alloy containing a eutectic, a diamond crystal mass and a silicon carbide or silicon nitride substrate are introduced, the diamond crystal mass being arranged between the substrate and the solid mass of the silicon-rich alloy containing a eutectic and with the substrate and the solid mass of the silicon-rich alloy or with at least one component for forming the eutectic-containing silicon-rich alloy is in contact and the eutectic-containing silicon-rich alloy is composed of silicon and a metal which forms a silicide with silicon; 909817/0942 Deutsche Bank Munich, account no. 82/08050 (BLZ 70070010) Postal check Munich No. 163397-802 b) the container and its contents in an energy-transmitting powder medium be arranged, which transmits the acting pressure essentially undiminished and during the hot-pressing process remains essentially unsintered; c) a substantially isostatic pressure is exerted on the container and its contents via the powder medium, which sufficient to stabilize the dimensions of the container and the contents substantially uniformly and thereby to create a dimensionally stable, essentially isostatic system of the powder-coated container, with the density the compressed mass of the diamond crystals over 7o Is volume percent of the volume of the compressed diamond crystals; d) the resulting isostatic system is a hot pressing process is subjected to form a liquid, eutectic-containing, silicon-rich alloy and this liquid, to float silicon-rich alloy into the spaces between the compressed mass of diamatite crystals and with to bring the contact surface of the substrate into contact, which is an interface with the compressed crystal mass forms, the hot-pressing process at a hot-pressing temperature of below about 1600 ° C is carried out under a hot press pressure that is sufficient to remove the liquid, to float silicon-rich alloy into the interstices of the compressed diamond crystal mass, the a silicon-rich pesticide alloy containing eutectic or the solid components for forming the eutectic-containing silicon-rich alloy in an amount which are used at the hot-pressing temperature to form a silicon-rich alloy containing a eutectic is sufficient, which in turn is sufficient to fill the spaces between the compressed mass of diamond crystals and to wet the contact surface of the substrate, 909817/0942 in order to thereby fill the pores at the interface so that the interface is at least essentially pore-free, the hot-pressing process being carried out in an atmosphere that does not have any noticeable harmful influence the diamond crystals, the liquid, silicon-rich impregnation alloy or the substrate, and during the hot-pressing process less than 5 percent by volume of diamond crystals in non-diamond elemental carbon are converted and the non-diamond shaped carbon or the surfaces of the diamond crystals react with the liquid, silicon-poor alloy to form carbides; e) the resulting, hot-pressed, essentially isostatic System is maintained during cooling under a pressure that is at least substantially necessary for maintenance the dimensions of the hot-pressed system are sufficient; and f) the resulting composite material is removed at which the polycrystalline diamond body is bonded to the silicon carbide or silicon nitride substrate and which Diamond crystals in an amount of at least 70 percent by volume of the volume of the polycrystalline diamond body are present. 2. The method according to claim 1, characterized in that the diamond crystals with graded grain sizes in the range of about 1 to about 60 micrometers are used. 3. The method according to any one of claims 1 and 2, characterized in that that the liquid, high-silicon impregnating alloy is used in an amount ranging from about 25 to about 80 percent by volume of the volume of the compressed diamond crystal mass is sufficient. 909817/0942 4. The method according to any one of claims 1 to 3? characterized, that the density of the compressed mass of diamond crystals is from about 71 to about below 95 percent by volume of the volume of the compressed crystals is sufficient. 5. The method according to any one of claims 1 to 4 _9, characterized in that the solid mass of the silicon-rich alloy is used in the form of grains. 6. A method for producing a one-piece composite material from a polycrystalline diamond body and a Silicon carbide or silicon nitride substrate using a hot pressing process, characterized in that a) a recess is pressed into a pressure-transmitting powder medium, which essentially reduces the pressure acting transmits undiminished and remains essentially unsintered during the hot-pressing process; b) in the recess a solid mass from a eutectic containing silicon-rich alloy or solid components to form one containing a eutectic silicon-rich alloy, a diamond crystal mass, and a polycrystalline silicon carbide or silicon nitride substrate be introduced, the diamond crystal mass between the substrate and the solid mass of a eutectic containing, silicon-rich alloy is arranged and with the substrate and the solid mass of the silicon-rich Alloy or at least with one component to form the silicon-rich alloy containing a eutectic is in contact, and wherein the eutectic-containing, silicon-rich alloy of silicon and a metal which forms a silicide with silicon; c) the recess and its contents with an additional amount of the 909817/034 2 28A5834 Pressure-transmitting powder medium are covered and thereby the recess with the pressure-transmitting powder medium is enveloped; d) on the recess and its contents via the powder medium an essentially isostatic pressure is exerted which is sufficient for the dimensions of the recess and its contents to stabilize essentially uniformly and thereby a dimensionally stable, essentially isostatic System of creating a powder-coated recess, the density of the compressed mass of diamond crystals is over 70 percent by volume of the volume of the compressed diamond crystals; e) the essentially isostatic system is subjected to a hot-pressing process in order to form a liquid, silicon-rich impregnation alloy containing a eutectic and to flood this liquid, silicon-rich alloy into the interstices of the compressed diamond crystal mass and to bring it into contact with the contact surface of the substrate with the pressed crystal mass forms an interface, the hot pressing ^{process being carried out at a hot pressing temperature of below about 1600 0} C under a hot pressing pressure that is sufficient to flood the liquid, silicon-rich alloy into the interstices of the pressed diamond crystal mass, the silicon-rich solid alloy containing a eutectic or the Components for forming the eutectic-containing, silicon-rich alloy are used in an amount which, at the hot-pressing temperature, to form a liquid, eutectic-containing, silicon-free Chen alloy is sufficient, which in turn is sufficient to fill the gaps in the compressed diamond crystal mass and to wet the contact surface of the substrate and thereby fill the pores at the interface, so 9098 17/09 4 2 that the interface is at least essentially free of pores, the hot-pressing process being carried out in an atmosphere that has no noticeable, harmful influence on the Has diamond crystals or the liquid, silicon-rich impregnation alloy or the substrate, and during the hot pressing process less than 5 percent by volume of diamond crystals in non-diamond-shaped elemental carbon are converted and the non-diamond-shaped carbon or the surfaces of the diamond crystals with the liquid, silicon-rich alloy reacts to form carbides; f) the hot-pressed, essentially isostatic system is maintained during cooling under a pressure at least substantially to maintain the dimensions the hot-pressed system is sufficient; and g) the resulting composite material is removed, in which the polycrystalline diamond body with the silicon carbide or silicon nitride substrate and the diamond crystals in an amount of at least 70 percent by volume of the volume of the polycrystalline diamond body. 7. The method according to claim 6, characterized in that the pesticide mass of the silicon-rich alloy in grained Shape is used. 8. composite material of a polycrystalline diamond body and a silicon carbide or silicon nitride substrate, characterized in that the polycrystalline diamond body is made in one piece with a polycrystalline substrate Silicon carbide or silicon nitride is connected, the polycrystalline diamond body from a mass of diamond crystals 909817/0942 consists, which are interconnected by a Siliciumatorae containing Binders are firmly connected, which comprises silicon carbide and a carbide and / or silicide of a metal component, which forms a silicide with silicon, the diamond crystals have a size of about 1 to about 1000 micrometers, the Diamond crystal roofs of the body of about 70 percent by volume to about below 9o volume percent of the volume of the diamond body is sufficient, the proportion of the binder containing silicon atoms is up to about 3o volume percent of the body, the Binder is at least substantially uniformly distributed in the body in contact with the surfaces of the diamond crystals standing part of the binder is at least for the most part silicon carbide, the diamond body is at least substantially is pore-free, the density of the substrate from about 85 to about 100 percent of the theoretical density of silicon carbide or from 80 to 100 percent of the theoretical density of silicon nitride and contains silicon carbide in an amount of at least 90 percent by weight of the substrate and is free from components which have a marked deleterious influence on the mechanical properties of the composite material, the polycrystalline diamond bodies have an interface with the silicon carbide or silicon nitride substrate and the binder extends from the polycrystalline diamond body to the contact surface with the substrate and at least essentially the pores fills at the interface, so that the interface is at least substantially pore-free. 9. Composite material according to claim 8, characterized in that the binder also contains elemental silicon. 10. Composite material according to one of claims 8 or 9, characterized in that the density of the diamond crystals is from about 7o volume percent to about 89 volume percent of the Diamond body is enough. 909817/094 11. Composite material according to one of claims 8 to 1o, characterized in that the diamond crystals in the Large are graded and the grain size from about 1 to about 6o micrometers is enough. 12. Composite material according to one of claims 8 to 11, characterized in that the binder is made of silicon carbide and metal silicide. 13. Composite material according to claim 12, characterized in that the binder contains elemental silicon. 14. Composite material according to one of claims 12 to 13 » characterized in that the metal component of the metal silicide is selected from the group consisting of cobalt, chromium, Iron, hafnium, manganese, molybdenum, niobium, nickel, paladium, pia tin, marriage ium, ehodium, rhutenium, tantalum, thorium, titanium, Uranium, vanadium, tungsten, tttrium, zirconium and alloys this includes metals. 15. Composite material according to one of claims 8 to 11, characterized in that the binder is made of silicon carbide and metal carbide. 16. Composite material according to claim 15 *, characterized in that that the metal component of the metal carbide is selected from the group consisting of chromium, hafnium, titanium, zirconium, Tantalum, vanadium, tungsten, molybdenum and alloys of these metals includes. 17. Composite material according to one of claims I5 and 16, characterized in that the binder contains elemental silicon. 909817/0942