Coating of ultra-hard materials

摘要

A unit which comprises a body (10) of ultra-hard material such as CVD diamond has a layer (16) of plasma spray cemented carbide bonded to a surface (14) thereof. The bonding is achieved through a bonding layer comprising an inner region (18) bonded to the surface (14) and comprising a minor amount of a carbide-forming metal and a major amount of a ductile metal and an outer region (20) bonded to the cemented carbide layer (16) comprising nickel, cobalt, iron or an alloy containing one or more of these metals. <IMAGE>