Patent ID: 6056999
Filing Date: 2000-05-02
Classification: C23C

Abstract:
A process for forming a titanium carbonitride TiC.sub.x N.sub.y coated cemented carbide insert, said cemented carbide insert comprising about 70 to 97 percent by weight tungsten carbide and a matrix binder comprising cobalt, wherein said process comprises chemically vapor depositing a layer of titanium carbonitride on said cemented carbide insert by heating gaseous reactants comprising titanium chloride, a hydrocarbon gas, hydrogen, and nitrogen under suitable conditions to form a TiC.sub.x N.sub.y coated insert having a ratio of x/y ranging from about 0.4 to about 1.5, wherein x is a number from about 0.3 to about 0.6, and y is a number from about 0.7 to about 0.4, having an eta phase in cemented carbide substrate areas adjacent said TiC.sub.x N.sub.y coating, said eta phase comprising chemical compounds consisting essentially of cobalt, tungsten and carbon, and contacting said TiC.sub.x N.sub.y coating with a carburizing gas for a sufficient time and at a sufficient temperature to convert substantially all of said eta phase to elemental cobalt and tungsten carbide.