SURFACE-COATED CERMET CUTTING TOOL WITH HARD COATING LAYER OF EXCELLENT THERMAL SHOCK RESISTANCE AND SURFACE LUBRICATABILITY

摘要

PROBLEM TO BE SOLVED: To provide a surface-coated cermet cutting tool with hard coating layer of excellent thermal shock resistance.;SOLUTION: This surface-coated cermet cutting tool has the hard coating layer constituted of (a) to (c) on a surface of a tool base body constituted of WC group cemented carbide or TiCN group cermet: (a) A Ti compound layer is constituted of one layer or more than two layers among a TiC layer, a TiN layer, a TiCN layer, a TiCO layer and a TiCNO layer which are all chemically evaporated and formed as a lower layer, and has the total average layer thickness of 3 to 20 μm. (b) A heating transformed α type Al₂O₃ layer formed by transforming a crystal structure into an α type crystal structure by applying heat treatment to Al₂O₃ having a κ type or θ type crystal structure in a state of being chemically evaporated and formed as an upper layer, having a structure of dispersing-distributing a heating transformed crack and the average layer thickness of 1 to 15 μm. (c) A Ti oxide layer is chemically evaporated and formed as a surface layer, and satisfying 1.2 to 1.9 in the atomic ratio of X to Ti by measuring a thickness directional central part by an Auger spectral analyzer when expressed by a composition formula : TiO_x, and having the average layer thickness of 0.1 to 5 μm.;COPYRIGHT: (C)2004,JPO&NCIPI