Physical Properties of Diamond Coatings on a WC—6% Co Substrate

We have investigated the physical properties,including the morphology,texture,adhesion and chemical quality,of high-frequency chemical vapour deposited diamond coatings on WC-6% Co substrates,which were pre-treated by a two-step etching method.The results indicate that the increasing Co content from 0.12 to 3.05% within the etching depth of 5μm caused a morphology transformation from prism diamond to spherulitic diamond,and a texture transformation from a {111} orientation to a {110} orientation.The Raman spectrum shows that the spherulitic diamond film contains more non-diamond phases (graphite,amorphous carbon and diamond-like carbon,etc) and has lower chemical quality than diamond films on a WC-6% Co substrate.The diamond coating grain sizes became about four times smaller when the deposition temperatures on the substrate surface were reduced from 1000 to 900℃.Compared with spherulitic diamond films,the prism diamond films exhibit better adhesion on the WC-6% Co substrate.