Production of diamond compacts consisting essentially of diamond crystals bonded by silicon carbide

Claim 1

A process for producing a diamond compact consisting essentially of diamond crystals bonded by silicon carbide, said process comprising the steps of: (1) intimately mixing diamond crystals with silicon in the proportions of about 97 to 65 percent weight of diamond to about 3 to 35 percent by weight of silicon to produce an intimate mixture of the diamond crystals and silicon; (2) confining said intimate mixture of diamond crystals and silicon in a pressure vessel together with one or more bodies of silicon in contact with or immediately adjacent to said intimate mixture within the pressure vessel; and (3) subjecting said intimate mixture of diamond crystals and silicon and said one or more bodies of silicon within the pressure vessel to a temperature above the melting point of silicon in the range of about 1,100° to 1,800° C. and to pressure in the range of about 10 to 40 kilobars so as to cause melting of the silicon in said intimate mixture and melting of said one or more bodies of silicon and infiltration of silicon from said one or more bodies into the interstitial spaces between the diamond crystals and to cause most of the silicon between the diamond crystals to react with diamond to produce silicon carbide, said silicon carbide forming a bond between diamond crystals, the overall proportions of diamond and silicon being such as to produce a compact containing between about 50 and 85 volume percent of diamond with a density of at least 3.35 g/cm 3 and a compressive strength of at least 10 kilobars.