Abstract: Broadly, the present invention is directed to polycrystalline diamond of improved thermal conductivity. The novel polycrystalline diamond consists essentially of at least 99.5 wt-% isotopically-pure carbon-12 or carbon-13. The inventive polycrystalline diamond is formed from at least 99.5 wt-% isotopically-pure carbon-12 or carbon-13. Single-crystal isotopically-pure carbon-12 and carbon-13 diamond are known to possess improved thermal conductivity. Polycrystalline diamond, however, possesses lower thermal conductivity patterns deleteriously impacted by, for example, impurities, isotopic effects, and grain boundary scattering. In fact, grain boundary scattering would lead the skilled artisan to believe that the thermal conductivity of polycrystalline diamond would be substantially unaffected by the isotopic nature of the diamond itself.

Abstract: The present invention relates to a method for growing diamond on a diamond substrate by chemical vapor deposition. The inventive method comprises alternatingly contacting at elevated temperature said diamond substrate with a gas having the formula C.sub.n X.sub.m and then with a gas having the formula C.sub.l Z.sub.p. X and Z each form single bonds with carbon. X and Z also are reactable to form ZX or a derivative thereof. The Z--X bond is stronger than the C--X bond and also is stronger than the C--Z bond. In the formulas, n, m, l, and p are integers. If C.sub.n X.sub.m and C.sub.l Z.sub.p do not react in the gas phase, then a gas mixture of them can be used to grow diamond instead of the alternating exposure of one and then the other.

Abstract: Broadly, the present invention is directed to a method for achieving high pressure wherein a sample is placed between a pair of diamond anvils and the anvils compressed. The improvement comprises forming the anvils from one or more of isotopically-pure .sup.12 C or .sup.13 C diamond. Isotopically-pure .sup.13 C diamond is preferred as it has the highest atomic or bond density parameter of any known material and, therefore, should have the highest hardness also Isotopically-enriched diamond .sup.13 C diamond should find utility as an anvil with higher .sup.13 C contents increasing the hardness of the anvil product. By utilizing isotopically pure diamond anvils, less breakage at current pressures should be realized concomitant with the ability to achieve yet higher pressures.

Abstract: Broadly, the present invention is directed to a method for making a thermally stable, dense, electrically conductive diamond compact. The method comprises infiltrating a mass of diamond crystals with a silicon infiltrant in the presence of boron under conditions comprising a temperature of not substantially above 1200 .degree. C. and a pressure of not substantially above 45 Kbars. The resulting compact contains diamond-to-diamond bonding. The boron can be provided in the form of boron-doped diamond. Alternatively, a boron-silicon alloy can be used for infiltrating boron-doped or undoped diamond. Further, boron can be added as elemental boron or B.sub.4 C with silicon for infiltration. Alternatively, boron metal catalyst plus silicon infiltration can be used for boron-doped or undoped diamond. Combinations of these techniques also can be used. In the HP/HT process, the silicon infiltrates the diamond powder mass forming a network composed of silicon carbide by reaction of the silicon with diamond-carbon.

Abstract: The invention provides grinding tools comprising thermally stable polycrystalline diamond or cubic boron nitride abrasive particles and single crystal diamond or cubic boron nitride abrasive particles attached to a support means via a bonding matrix such as a sintered or electrodeposited metal or alloy matrix, a resinous matrix, or a vitreous matrix.

Abstract: Disclosed is an improved method for making a polycrystalline diamond compact comprising subjecting a mass of diamond particles, which mass is adjacent a cemented metal carbide mass containing a catalyst, to a high pressure/high temperature process which results in a compact characterized by diamond-to-diamond bonding. The improvement in such process comprises placing a second catalyst source adjacent the diamond mass, said second catalyst having a melting point which is lower than the melting point of the catalyst of the carbide; and subjecting said mass to high pressure/high temperature sintering at a temperature above the melting point of the second catalyst, but below the melting point of the carbide catalyst, for causing said second catalyst to selectively diffuse through said mass for forming said polycrystalline diamond compact. The preferred catalyst is a mixture of cobalt and boron.

Abstract: The present invention provides saw blade segments comprising polycrystalline diamond cutting elements and single crystal diamond cutting elements dispersed in a bonding matrix. In a preferred embodiment abrasion resistant particles are included so as to cause non-uniform wearing of the cutting segments. In another aspect of the invention, cutting segments are provided which utilize surface set polycrystalline diamond cutting elements larger than mesh size 18.

Abstract: Disclosed is an improved method for making a polycrystalline diamond compact comprising subjecting a mass of diamond particles, which mass is adjacent a cemented metal carbide mass containing a catalyst, to a high pressure/high temperature process which results in a compact characterized by diamond-to-diamond bonding. The improvement in such process comprises placing a second catalyst source adjacent the diamond mass, said second catalyst having a metal point which is lower than the melting point of the catalyst of the carbide; and subjecting said mass to high pressure/high temperature sintering at a temperature above the melting point of the second catalyst, but below the melting point of the carbide catalyst, for causing said second catalyst to selectively diffuse through said mass for forming said polycrystalline diamond compact. The preferred catalyst is a mixture of cobalt and boron.

Abstract: Disclosed is a method for making re-sintered polycrystalline CBN compact which comprises placing sintered boron-rich polycrystalline CBN particles in a high temperature/high pressure apparatus and subjecting said boron-rich CBN particles to a pressure and a temperature adequate to re-sinter said particles, the temperature being below the reconversion temperature of CBN, for a time sufficient to re-sinter the polycrystalline CBN particles therein. The boron-rich polycrystalline CBN particles in the HP/HT apparatus contain no impurity which would interfere with the sintering process (CBN sintering inhibiting impurities) and no sintering aid material.

Abstract: Optical windows for hostile environments have been made from diamond and adamantine boron nitride compacts. The compact windows can comprise a single layer of large crystals bonded in a matrix. For example, they are made by exposing a sample of diamond (425-1700 micron) in a diamond and graphite matrix to high pressure-high temperature conditions (e.g., 50 Kbar at 1400.degree. C. to 85 Kbar at 1800.degree. C.).A typical boron nitride reaction zone assembly (cell) is shown in FIG. 1, in which carbon heater tube 1 is surrounded by tantalum foil sleeve 2. The sample of pyrolytic boron nitride 3 is disposed between carbon discs 5, tantalum foil discs 4 and hot pressed boron nitride plugs 6.The optical windows produced are capable of transmitting infrared light and visible light.

Abstract: A dressing method has been devised for plated grinding wheels having relatively coarse mesh microcrystalline cubic boron nitride abrasive. The method comprises lightly grinding cemented metal carbide (e.g. cobalt cemented tungsten carbide) with the grinding wheel before grinding the intended workiece. Wheels dressed in this manner have been found to obtain good surface finishes (16-18 RMS) while maintaining a free cutting aggressive action which gives high grinding rates.

Abstract: An improved metal coated abrasive is prepared with a controlled, rough textured surface, which surface has improved adherence to resinous materials when said coated abrasives are incorporated into resin bonded tools. Disclosed is a process for achieving this rough texture through a modification to the known electroless or autocatalytic techniques for coating abrasives with metals such as copper and nickel. The improvement comprises: interrupting the electroless coating process by passivating the surface one or more times; and then reactivating the passivated surface each time with a catalytic material whereby an array of preferential sites for metal deposition is obtained; and resuming normal electroless coating.

Abstract: Disclosed is an improved process for preparing a composite compact wherein a mass of abrasive crystals, a mass of metal carbide, and a bonding medium are subjected to a high-temperature/high pressure process for providing a composite compact. The sintered carbide mass supports the mass of abrasive crystals and bonding or catalyst metal, and the abrasive crystal grains are directly bonded to adjacent crystal grains in the mass thereof. Such improved process comprises disposing the mass of abrasive crystals in layers wherein the coarsest layer is closest to the carbide mass and is composed of crystals having a largest dimension of between about 75 and 500 microns and the finest layer is disposed farthest away in the carbide mass and is composed of crystals having a largest dimension of less than 10 microns.

Abstract: In one embodiment, a compact for tools, such as cutting, drilling and shaping tools, consists essentially of self-bonded abrasive particles. The bonded particles define a substantially continuous interconnected network of pores, dispersed throughout the compact. The method for making such a compact comprises the steps of bonding a mass of abrasive particles, aided by a sintering aid material, under high temperatures and pressures (HP/HT) to form an abrasive body comprised of said particles in a self-bonded form and said material infiltrated throughout the body. The body is then treated to remove substantially all infiltrated material, thereby to produce a compact consisting essentially of the self-bonded abrasive particles. In another embodiment, a composite compact which is made in a similar manner to the first embodiment consists essentially of a layer of self-bonded abrasive particle and a substrate layer (preferably of cemented carbide) bonded to the abrasive particle layer.

Abstract: In one embodiment, a compact for tools, such as cutting, drilling, wire drawing and shaping tools, consists essentially of a porous mass of self-bonded, boron-doped diamond particles and a catalyst-solvent material. The method for making such a compact comprises the steps of bonding a mass of boron-doped diamond particles, aided by a catalyst-solvent material, under high temperatures and high pressures (HP/HT).In another embodiment, a composite compact, which is made in a similar manner to the first embodiment, consists essentially of (i) a layer of a porous mass of self-bonded, boron-doped diamond particles and catalyst-solvent material; and (ii) a substrate layer of cemented carbide bonded to the diamond layer.

Abstract: An improvement for making polycrystalline compacts containing single crystal diamonds embedded therein is disclosed. Cracking of such compacts is minimized by isolating the diamond in a relatively compressible matrix before exposing the sample to high pressure-high temperature sintering conditions. This may be done, for example, by mixing the diamond crystals with graphite or amorphous carbon powder. Useful devices which can be made from such compacts are cutting tools and wire drawing dies.A sectional view of a wire die blank of this invention is depicted in FIG. 3. One single crystal diamond 12 is embedded in polycrystalline diamond matrix 14 which has been sintered within cemented tungsten carbide ring 16. The wire is drawn through aperture 18. It is felt that this type of die would improve the wire finish while helping to prevent the failure of the single crystal through cleavage. It is useful in drawing wires made of such materials as tungsten, copper coated steel, copper and nickel.

Abstract: An improvement in the manufacture of diamond compacts is disclosed in which a cylindrical mass of polycrystalline diamond is surrounded by and bonded to an outer mass of metal which provides support for the diamond. The improvement comprises the use of seed diamond to grow the polycrystalline mass under high pressure-high temperature (HP/HT) conditions from non-diamond carbon, utilizing a catalyst metal contained in the outer metal annulus. Preferably, this improved process is carried out using a cup-shaped metal mass having a stable carbide content of at least 10% and a coefficient of thermal expansion slightly higher than diamond. It is also preferred to heat the sample (the outer metal mass and the inner graphite mass) directly by passing an electric current through the outer metal mass in the HP/HT process during which the polycrystalline compact is formed.

Abstract: Compacts are provided in which one or more single crystal diamonds, having a largest dimension of at least one millimeter, are embedded in the polycrystalline matrix which may be made of diamond; cubic boron nitride (CNB); and silicon and silicon carbide bonded diamond, CBN, or mixtures of diamond and CBN. The single crystal diamond is from 10-90 volume percent of the compact.The compacts (except for the silicon and silicon carbide variety) are made by high pressure-high temperature processing generally in the range of 50 Kbar at 1300.degree. C. to 85 Kbar at 1750.degree. C.They have applications in several fields, for example, wire drawing die blands, cutting tool blanks, and anvils for high pressure apparatus.

Abstract: In one embodiment, a compact for tools, such as cutting, drilling and shaping tools, consists essentially of self-bonded abrasive particles. The bonded particles define a substantially continuous interconnected network of pores, dispersed throughout the compact. The method for making such a compact comprises the steps of bonding a mass of abrasive particles, aided by a sintering aid material, under high temperatures and pressures (HP/HT) to form an abrasive body comprised of said particles in a self-bonded form and said material infiltrated throughout the body. The body is then treated to remove substantially all infiltrated material, thereby to produce a compact consisting essentially of the self-bonded abrasive particles. In another embodiment, a composite compact which is made in a similar manner to the first embodiment consists essentially of a layer of self-bonded abrasive particle and a substrate layer (preferably of cemented carbide) bonded to the abrasive particle layer.

Abstract: An improved resinoid grinding wheel particularly useful for the wet or dry grinding of hardened steels and steel alloys utilizes nickel-coated cubic boron nitride particles as the abrasive medium.