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

摘要

PROBLEM TO BE SOLVED: To provide a cutting tool of surface-coated cermet with a hard coating layer having excellent thermal shock resistance. SOLUTION: This cutting tool of surface-coated cermet is manufactured by forming the hard coating layer on the surface of a tool base body composed of WC-based cemented carbide or TiCN-based cermet. The hard coating layer is composed of (a) a primer layer comprising a Ti compound layer composed of one layer or a lamination of two or more layers among a TiC layer, TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer formed by deposition, having average thickness of 3-20μm, and (b) an upper layer comprising a composite doubleα-type Al2O3layer composed of a lower layer of a heat transformedα-type Al2O3layer havingα-type crystal structure formed by applying heat-transformation treatment to Al2O3having aκ-type crystal structure as formed by deposition, having texture in which transformation cracks generated by the heat transformation treatment are dispersed and distributed, and having average layer thickness of 3-15μm, and an upper layer of depositedα-type Al2O3layer of anα-type crystal structure formed by deposition, and having average layer thickness of 0.5-2μm. COPYRIGHT: (C)2004,JPO&NCIPI