Diamond-coated cemented carbide cutting inserts

Abstract The diamond-coated cemented carbide (WC-6%Co) inserts have been produced using a CVD intermediate tungsten layer (∼5 m) between substrate and diamond. Diamond films about 15 m thick were grown in ASTex and a pilot plant with anomalous glow discharge plasma using H 2 -CH 4 (10%)-O 2 (1%) and H 2 -CH 4 (1%) mixtures, respectively. Gas pressure, temperature and growth rate in both cases were about 10 kPa, 800 °C, and 7 m h −1 . Chemical and phase composition of tungsten and diamond coatings have been studied by electron probe microanalysis and X-ray diffraction. The wear resistance of the inserts was estimated by the turning of Al-12%Si alloy. It has been shown that wear resistance of the inserts increases by about three times compared with PCD tools.