Patent ID: 6413628
Filing Date: 2002-07-02
Classification: C23C,Y10T

Abstract:
A titanium carbonitride coated cemented carbide insert which comprises:a cemented carbide substrate comprising tungsten carbide and a matrix binder comprising cobalt, a coating of titanium carbonitride TiCxNy deposited on said cemented carbide substrate by heating gaseous reactants comprising titanium chloride, methane, hydrogen and nitrogen under suitable conditions to form a TiCxNy coated insert having an eta phase in the substrate areas adjacent said titanium carbonitride coating, said eta phase comprising chemical compounds consisting essentially of cobalt, tungsten and carbon, and contacting said TiCxNy coated insert with a carburizing gas for a sufficient time and at sufficient temperature to convert substantially all of said eta phase to elemental cobalt and tungsten carbide, said titanium carbonitride coating comprising tungsten at grain boundaries of titanium carbonitride coating grains.