摘要:
An adherently bonded polycrystalline diamond body is produced by forming a charge composed of a mass of diamond crystals in contact with a mass of eutectiferous silicon-rich alloy wherein the alloy is in contact or in association with hexagonal boron nitride, confining such charge within a reaction chamber, subjecting the confined charge to a pressure of at least 25 kilobars, heating the pressure-maintained charge to a temperature sufficient to melt the alloy and at which no significant graphitization of the diamond occurs whereby the alloy infiltrates through the interstices between the diamond crystals producing said body.
摘要:
A mass of diamond crystals contacting a mass of elemental silicon are confined within a pressure-transmitting medium. The resulting charge assembly is subjected to a pressure of at least 25 kilobars causing application of isostatic pressure to the contacting masses which dimensionally stabilizes them and increases the density of the mass of diamond crystals. The resulting pressure-maintained charge assembly is heated to a temperature sufficient to melt the silicon and at which no significant graphitization of the diamond occurs whereby the silicon is infiltrated through the interstices between the diamond crystals producing, upon cooling, an adherently bonded integral body.
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 nitride 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 nitride substrate sufficiently producing, upon cooling, an adherently bonded integral composite.
摘要:
A mass of diamond crystals in contact with a mass of eutectiferous silicon-rich alloy 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 producing, upon cooling, an adherently bonded integral body.
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:
A self-lubricating cemented carbide cutting tool of special utility in titanium machining having a copper coating bearing a film of copper iodide is provided by coating the tool with a layer of copper, heating to bond the copper to the cemented carbide and thereafter reacting the copper with iodine to form the film of desired thickness.
摘要:
A mass of cubic boron nitride(CBN) crystals, aluminum or aluminum alloy and a silicon carbide ceramic substrate are disposed in a container which is placed within a pressure-transmitting powder medium. Pressure ranging from about 20,000 psi to about 200,000 psi is applied to the powder medium resulting in substantially isostatic pressure being applied to the container and its contents. To the resulting shaped substantially-isostatic system of powder-enveloped container, heat and pressure are applied simultaneously whereby the aluminum or aluminum alloy is liquefied and infiltrated through the interstices between the CBN crystals and diffused into the contacting face of the silicon carbide substrate sufficiently to produce, upon cooling, an adherently bonded integral composite.
摘要:
A self-sharpening refractory metal cutting tool presenting an overhanging cutting portion, i.e. a flange, or ledge, of width equal to (or slightly greater than) the depth of the cut to be taken and maximum thickness equal to tolerable tool flank wear is disclosed. This tool construction has special utility in a novel high-speed cutting method in which only the tool flange does the cutting in which operation the flange is worn away with the wear progressing lengthwise of the flange during which time the flange sequentially performs a roughing cut and then a finishing cut in a single pass.
摘要:
A particulate mixture of ceramic powder, free carbon and a hydride of a metal selected from the group consisting of hafnium, niobium, tantalum, titanium, vanadium, zirconium and mixtures thereof is hot pressed decomposing the hydride and reacting the resulting metal with carbon producing a polycrystalline microcomposite comprised of a continuous phase of the carbide of the metal which encapsulates at least about 20% by volume of the ceramic particles and which either encapsulates or is intermixed with the balance of said ceramic particles.