DIAMOND-COATED BODIES AND PROCESS FOR PREPARATION THEREOF

摘要

A diamond-coated body is prepared by coating a dimaond film on the surface of a sintered body by means of vapor phase synthesis, the sintered body being so prepared by subjecting a sintered body prepared from ceramics based on silicon nitride to heat treatment at the temperature of 1,400 .degree.C to 1,700 .degree.C as to give a crystalline intergranular phase. The resulting diamond-coated body has excellent adhesion between the diamond film and the substrate and it is appropriately employed for cutting tools and so on because, when applied to the cutting tools, they can be used for cutting for a long period of time.