Patent ID: 6080477
Filing Date: 2000-06-27
Classification: C23C,Y10T

Abstract:
A titanium carbonitride coated cemented carbide article made according to a process comprising chemically vapor depositing a layer of titanium carbonitride directly on a cemented carbide substrate having a cobalt enriched surface by heating gaseous reactants comprising titanium chloride, methane, hydrogen and nitrogen with an optimum carbon/nitrogen ratio, under suitable conditions to form a titanium carbonitride coated cemented carbide article having an eta phase in the substrate adjacent said titanium carbonitride coating, said eta phase comprising chemical compounds consisting essentially of cobalt, tungsten and carbon, and contacting said coated article 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 article having a normalized and regular coating/substrate interface and an interfacial region consisting essentially of carbon, titanium carbonitride and tungsten in a form unreacted with cobalt.