摘要:
Polycrystalline compacts include a polycrystalline superabrasive material comprising a first plurality of grains of superabrasive material having a first average grain size and a second plurality of grains of superabrasive material having a second average grain size smaller than the first average grain size. The first plurality of grains is dispersed within a substantially continuous matrix of the second plurality of grains. Earth-boring tools may include a body and at least one polycrystalline compact attached thereto. Methods of forming polycrystalline compacts may include coating relatively larger grains of superabrasive material with relatively smaller grains of superabrasive material, forming a green structure comprising the coated grains, and sintering the green structure. Other methods include mixing diamond grains with a catalyst and subjecting the mixture to a pressure greater than about five gigapascals (5.0 GPa) and a temperature greater than about 1,300° C. to form a polycrystalline diamond compact.
摘要:
A polycrystalline compact includes diamond, cubic boron nitride, and at least one hard material, which may be aluminum nitride, gallium nitride, silicon nitride, titanium nitride, silicon carbide, titanium carbide, titanium boride, titanium diboride, and/or aluminum boride. The diamond, the cubic boron nitride, and the hard material are intermixed and interbonded to form a polycrystalline material. An earth-boring tool includes a bit body and a polycrystalline diamond compact secured to the bit body. Methods of fabricating polycrystalline compacts include forming a mixture comprising diamond, non-cubic boron nitride, and a metal or semimetal; encapsulating the mixture in a container; and subjecting the encapsulated mixture to high-pressure and high-temperature conditions to form a polycrystalline material.
摘要:
A self-grown monopoly compact grit and high pressure, high temperature process for preparing the same. The high pressure, high temperature sintered/synthesized monopoly compact grit is used in various industrial tools such as saw blades, grinding wheels, cutting tools and drill bits. Further, the monopoly compact grit of the present invention is produced from a seed of a mono-crystal of diamond or cubic boron nitride surrounded by either a self-grown crystal layer or an integrally bonded poly-crystalline sintered compact layer. The self-grown crystal layer is a new grown crystal structure where the seed crystal grows into a new phase through a normal diamond or cubic boron nitride synthesis process in the presence of a catalyst metal solvent. The compact layer is composed of about 50 to about 90 volume percent of diamond or cubic boron nitride, a typical binder material, which is a catalyst for crystal-to-crystal bonding, and a cementing agent which is a binding agent capable of forming stable carbide and nitride bonds.
摘要:
Diamonds are synthesized from SiC at temperatures and/or pressures lower than those required to convert amorphous carbon or graphite to diamond, by heating the SiC in the absence of another non-diamondaceous source of elemental carbon and in the presence of a reactant which selectively reacts with the Si at the temperature to which the SiC is heated, and in a matrix which is frangible when cooled, while the Sic is within the diamond stable region of the diamond-graphite phase diagram, thereby permitting the diamond to be separated therefrom by physical means.
摘要:
A polycrystalline diamond body infiltrated by a silicon atom-containing metal (e.g., silicon alloy) is bonded to a substrate comprising cemented carbide with a barrier of refractory material extending between the diamonds cemented together with silicon atom-containing binder and the substrate substantially precluding migration of the cementing medium (e.g., cobalt) from the carbide substrate into contact with the silicon atom-containing bonding medium in the diamond body. The process comprises subjecting a mass of diamond powder, a quantity of silicon atom-containing metal binder material, a cemented carbide body and a barrier made of material selected from the group consisting of tantalum, vanadium, molybdenum, zirconium, tungsten and alloys thereof to the simultaneous application of elevated temperature and pressure.
摘要:
A mass of diamond crystals in contact with a mass of eutectiferous silicon-rich alloy and a silicon carbide ceramic substrate are disposed in a container and placed within a pressure transmitting powder medium. Pressure is applied to the powder medium resulting in substantially isostatic pressure being applied to the container and its contents sufficient to dimensionally stabilize the container and its contents. The resulting shaped substantially isostatic system of powder-enveloped container is hot-pressed whereby fluid eutectiferous silicon-rich alloy is produced and infiltrated through the interstices between the diamond crystals and contacts the contacting face of the silicon carbide substrate sufficiently producing, upon cooling, an adherently bonded integral composite.
摘要:
THIS INVENTION relates to a method of making a diamond containing material comprising diamond particles and a second phase containing an intermetallic compound comprising the steps of providing a reaction mass of reactants capable, on reaction, of producing carbon and an intermetallic compound and subjecting the reaction mass to diamond synthesis conditions. In an embodiment of the invention, the diamond containing material produced is polycrystalline diamond (PCD) and the reaction mass contains diamond particles in an amount sufficient to allow PCD to be produced. In a further embodiment of the invention, the diamond content in the diamond containing material produced does not exceed 70 volume %.
摘要:
THIS INVENTION relates to a method of making a diamond containing material comprising diamond particles and a second phase containing an intermetallic compound comprising the steps of providing a reaction mass of reactants capable, on reaction, of producing carbon and an intermetallic compound and subjecting the reaction mass to diamond synthesis conditions. In an embodiment of the invention, the diamond containing material produced is polycrystalline diamond (PCD) and the reaction mass contains diamond particles in an amount sufficient to allow PCD to be produced. In a further embodiment of the invention, the diamond content in the diamond containing material produced does not exceed 70 volume %.
摘要:
An improved method for controlling nucleation sites during superabrasive particle synthesis can provide high quality industrial superabrasive particles with high yield and a narrow size distribution. The synthesis method can include forming a raw material layer, forming a particulate catalyst layer adjacent the raw material layer, and placing crystalline seeds in a predetermined pattern at least partially in the catalyst layer or raw material layer to form a growth precursor. Alternatively, the raw material and catalyst material can be mixed to form a particulate crystal growth layer and then placing the crystalline seeds in a predetermined pattern in the growth layer. Preferably, seeds can be substantially surrounded by catalyst material. The growth precursor can be maintained at a temperature and pressure at which the superabrasive crystal is thermodynamically stable for a time sufficient for a desired degree of growth. The crystalline seeds can be placed in a predetermined pattern using a template, a transfer sheet, vacuum chuck or similar techniques. The superabrasive particles grown using the described methods typically have a high yield of high quality industrial particles and a narrow distribution of particle sizes.
摘要:
A method for removing defects at high pressure and high temperature (HP/HT) or for relieving strain in a non-diamond crystal commences by providing a crystal, which contains defects, and a pressure medium. The crystal and the pressure medium are disposed in a high pressure cell and placed in a high pressure apparatus, for processing under reaction conditions of sufficiently high pressure and high temperature for a time adequate for one or more of removing defects or relieving strain in the single crystal.