Graphitization Process of Diamond Surfaces During the Sintering of Diamond-Cobalt System under Pressure and Temperature

The conditions of graphitization on diamond surface under high temperature and the graphitization process of diamond under high pressure and temperature were investigated experimentally. The graphitization on the surface of diamond near WC-Co substrate was discovered in samples sintered at the temperature below the cobalt-diamond eutectic point. The XRD testing results show that the diamond powders experienced three graphitization stages during the sintering process under high pressure and high temperature, they are, graphitization accelerated stage, climax stage and restrained stage.