| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface-covered cermet made cutting tool with a hard covering layer having excellent thermal impact resistance. SOLUTION: The surface-covered thermet made cutting tool is constituted to form the hard covering layer composed of (a) a Ti compound layer having an average layer thickness of 3-20μm as a lower layer and formed of lamination layers of one or two or more layers of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer which are formed by vapor deposition respectively, (b) a heat transformationαtype Al<SB>2</SB>O<SB>3</SB>layer having an average layer thickness of 3-15μm as an upper layer and having heat transformationαtype crystal structure from a Al<SB>2</SB>O<SB>3</SB>layer formed by vapor deposition and having k orθtype crystal structure, and having tissue in which heat transformation generation cracks are uniformly dispersed and distributed, and (c) a TiC layer or TiCM layer having an average layer thickness of 0.5-4μm as a surface layer and formed by vapor deposition, on a surface of a tool base composed of WC-based cemented carbide or TiCN-based cermet. COPYRIGHT: (C)2004,JPO
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