Method of making a diamond-coated composite body

摘要

At least the surface region of a cutting tool substrate made of tungsten carbide in a cobalt matrix is carburized to chemically passivate the cobalt prior to deposition of diamond film on it. The passivation improves adhesion by preventing reaction of the cobalt with the diamond in the course of the deposition process. To further improve adhesion of the diamond, cobalt is removed from the exposed surfaces of the tungsten carbide grains by heat treatment in inert gas or by hydrogen plasma.