Patent ID: 6338894
Filing Date: 2002-01-15
Classification: C23C,Y10T

Abstract:
A coated cemented carbide cutting tool member, comprising: a substrate and a hard coating layer deposited on said substrate, wherein said hard coating layer has an average thickness of 3 to 25 &mgr;m and comprises:(1) at least one layer having an average thickness of 0.1 to 5 &mgr;m and comprising a granular Ti compound selected from the group consisting of TiC, TiN, T2O3, TiCO, TiNO, TiCNO and mixtures thereof; (2) a TiCN layer having an average thickness of 2 to 15 &mgr;m and comprising a longitudinal growth crystal structure: and (3) an Al2O3 layer having an average thickness of 0.5 to 8 &mgr;m; wherein said TiCN layer comprises a growth direction and a compositional gradient of carbon and nitrogen along said growth direction, the concentration of carbon decreasing and the concentration of nitrogen increasing from a lower portion of said TiCN layer to an upper portion of said TiCN layer, wherein said upper and lower portions are with respect to a surface of said substrate on which said layers are deposited.