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US 5,106,393 AGranted
Diamond compact possessing low electrical resistivity
AssigneeThe Australian National University
InventorAlfred E. Ringwood
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AssigneeThe Australian National University
InventorAlfred E. Ringwood
Estimating the term…
A diamond compact comprised of more than 60 volume percent and less than 90 volume percent of diamond crystals connected by a silicon carbide bond. The bond contains more than 500 parts per million of nitrogen and/or phosphorus and the compact possesses a low electrical resistivity of less than 0.2 ohm cm. The compact may be produced by a process in which the diamond crystals are intimately mixed with a bonding agent comprising silicon and the mixture is subjected within a confining space to a high temperature and pressure within the graphite stability field to cause silicon in the bonding agent to react extensively with carbon in the diamond crystals to form the silicon carbide bond. To produce the low electrical resistivity, a material containing nitrogen and/or phosphorus is introduced into the confining space prior to application of the high temperature and pressure conditions. In a modified process, the mixed diamond crystals and bonding agent are placed immediately adjacent to one or more bodies of silicon within the confining space prior to application of the high pressure and temperature conditions. In this process, the nitrogen and/or phosphorus containing material may be mixed with the diamond crystals and bonding agent and/or with one of the additional bodies of silicon prior to application of the high temperature and pressure conditions.
A diamond compact comprised of more than 60 volume percent and less than 90 volume percent of diamond crystals connected by a silicon carbide bond, said bond containing more than 500 parts per million of nitrogen and/or phosphorus, said compact possessing an electrical resistivity smaller than 0.2 ohm cm.
A diamond compact comprising of more than 60 volume percent and less than 90 volume percent of diamond crystals connected by a silicon carbide bond, wherein the diamond crystals have been plastically deformed so that they have abundant crystalline defects and form a closely packed rigid structure in which contacts between the diamond crystals occur over extended mating surfaces arising from plastic deformation of the diamond crystals during formation of the compact under pressure and temperature within the graphite stability field, the diamond crystals being bonded together by said silicon carbide bond formed by reaction of a bonding agent comprising silicon with carbon in the diamond crystals during the formation of the compact under said pressure and temperature conditions, the silicon carbide bond having a minimum melting point greater than 1600.degree. C. in the presence of carbon and said compact possessing a compressive strength greater than 10 kbars, said bond containing more than 500 parts per million of nitrogen, phosphorous or both, said compact possessing an electrical resistivity smaller than 0.2 ohm cm.
A process for producing a diamond compact for cutting, turning, drilling, and otherwise working ultra-hard ceramics, carbides and rocks which comprises (i) intimately mixing a mass of particulate diamond crystals with a bonding agent comprising silicon in the proportions 60-95 volume percent of diamond to 40-5 volume percent of bonding agent;
Dependencies are inferred from the claim text.