| 摘要 |
1,246,227. Diamond compacts. UNITED STATES ATOMIC ENERGY COMMISSION. ,6 Oct., 1969 [8 Nov., 1968], No. 49001/69. Heading C1A. A dense Coherent compact of partioulate diamond is prepared by heating clean diamond particles having a particle size in the range of 0À3 to 60 microns to a a temperature in the range of 300‹ to 1000‹ C. while under a pressure below 10<SP>-5</SP> torr so as to condition the surface of the particles, and then compressing a mass of those particles so that the conditioned surfaces of the particles are in substantially direct contact to a pressure at least above the graphite to diamond transition point and simultaneously heating the compressed mass to a temperature above the graphite to diamond transition line and substantially in the diamond stable region so that sintering occurs and a direct particle to particle bond is produced between particles of the mass. Preferably the diamond particles are conditioned by heating to a temp. of 400-600‹ C. at a pressure below 10<SP>-6</SP> torr, and a preferred particle size is in the range 0À5 to 10 microns. At least 20 parts by weight of the diamond dust may have a particle size in the range 0À3 to 10 microns. The mass of diamond particles may be compressed to a pressure of at least 35 and heated to a temp. above 1300‹ C. The mass of diamond particles may include elementary material selected from B, Si and Be dust present in amounts below 3% by weight. The diamond used may be cleaned by washing successively with an organic solvent selected from low boiling ketones, chlorinated hydrocarbons, and degreasing solvents, and finally with an alcohol selected from methyl and ethyl alcohol. The amount of B, Si or Be dust present is preferably below 1% by weight and the mass is compressed to 55 to 80 kilobars and heated to 1600‹ to 2000‹ C. The compact so produced has a hardness on the Vickers scale of at least 7000.
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