Use of fired fibrous graphite in fabricating polycrystalline diamond and/or cubic boron nitride/silicon carbide/silicon composite bodies

摘要

Disclosed is an improvement in a process for fabricating a polycrystalline diamond and/or cubic boron nitride-silicon carbide- silicon composite body fabricated by infiltrating silicon through a mixture of a carbonaceous material and non-diamond carbon coated diamond and/or cubic boron nitride under partial vacuum at elevated temperature. Such improvement comprises providing fibrous graphite for inclusion in the mixture, said fibrous graphite being subjected to heat treatment at a temperature of between about 800 and 1700 C. prior to its inclusion in the mixture and at a temperature of between about 800 and 1550 C. after its inclusion in the mixture. Such heat treatment is conducted under a total pressure of less than about 1 Torr. The vacuum silicon infiltration then is practiced on the mixture which includes the heat treated graphite fibers.