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 de veloped barrier interlayers, well compatible with cemented carbides. T he barrier interlayer comprises a Ti-based layer adjacent to the subst rate, which completely prevents both substrate decarburization and Co diffusion from the substrate, and a diamond-bonding layer needed to ob tain high adhesion to the diamond coating. The diamond-bond layer is o btained by seeding the surface with nanograined diamond particles by l aser ablation. Diamond deposition under controlled parameters allows o ne to obtain fine-grained and uniform diamond coatings. The diamond co ating obtained in this way has a high adhesion to the cemented carbide substrate due to the enhanced interaction through the nanograined dia mond interlayer.