Patent attributes
A coated cutting tool can suppress film spalling due to adhesion. The tool has on its substrate an inner layer, intermediate layer, and outer layer. The inner layer is composed of at least one material selected from the group consisting of the carbide, nitride, carbonitride, boride, boronitride, borocarbonitride, oxide, oxycarbide, oxynitride, and oxycarbonitride of the elements belonging to the IVa, Va, and VIa groups. The inner layer includes at least one layer having a columnar-crystal structure. The outer layer is composed of at least one oxide selected from the group consisting of aluminum oxide, zirconium oxide, hafnium oxide, and their solid solutions. The intermediate layer is composed of titanium boronitride, TiBxNy (x, y: atomic %), that satisfies 0.001<x/(x+y)<0.04. The intermediate layer has an average thickness of 0.1 to 1 μm and a surface roughness of 50 to 500 nm expressed by the vertical distance between the peak and valley lines within a reference length of 1 μm.
