Thickened α-type surface-coated cermet cutting tools which exhibits chipping resistance of the aluminum oxide layer has excellent

摘要

PROBLEM TO BE SOLVED: To provide a surface coated cermet cutting tool having a thick α type Al₂O₃ layer exhibiting excellent chipping resistance.;SOLUTION: The hard coating layer composed of the following (a) and (b) is formed on the surface of a tool base substance composed of WC-based cemented carbide or TiCN-based cermet. The lower layer (a) is Ti compound layer which is composed of one or more layers formed by chemical vapor deposition, and has total average layer thickness of 0.5 to 10 μm. The upper layer (b) is the thick reformed α type Al₂O₃ layer which has α type crystal structure in a state formed by chemical vapor deposition, reprents a specific inclination angle frequency distribution graph in which the inclination angle formed by a normal line of (0001) surface of a crystal surface of the crystal grains is measured by using a field emission type scanning electron microscope, the measured inclination angle within the range of 45 to 90 degree among the measured inclination angle is divided for every 0.25 degree pitch, and the frequency existing in each division is totaled, and which has an average layer thickness of 16 to 30 μm.;COPYRIGHT: (C)2007,JPO&INPIT