Highly adherent diamond coatings deposited onto WC-Co cemented carbides via barrier interlayers

Diamond coatings have been deposited by plasma enhanced chemical vapor deposition (PCVD) onto WC-Co cemented carbides by use of specially developed barrier interlayers, well compatible with cemented carbides. The barrier interlayer comprises a Ti-based layer adjacent to the substrate, which completely prevents both substrate decarburization and Co diffusion from the substrate, and a diamond-bonding layer needed to obtain high adhesion to the diamond coating. The diamond-bond layer is obtained by seeding the surface with nanograined diamond particles by laser ablation. Diamond deposition under controlled parameters allows one to obtain fine-grained and uniform diamond coatings. The diamond coating obtained in this way has a high adhesion to the cemented carbide substrate due to the enhanced interaction through the nanograined diamond interlayer.