| abstract |
A coated hard alloy excellent in wearing resistance, chipping resistance, welding resistance, and coating adhesion. The coated hard alloy has on the surface thereof an inner layer, an intermediate layer, and an outer layer. The inner layer comprises a layer of at least one member selected among the carbides, nitrides, borides, and oxides of elements in Groups IVa, Va, and VIa of the Periodic Table and solid solutions of these. The intermediate layer comprises a layer of at least one member selected among aluminum oxide, zirconium oxide, and solid solutions of these. The outer layer comprises a titanium carbonitride layer having a columnar structure. The coated hard alloy has a section in which the maximum roughness of the surface of the intermediate layer, Amax, and that of the surface of the titanium carbonitride layer having a columnar structure in the outer layer, Bmax, satisfy the relationship 1: (Bmax/Amax)<1 wherein 0.5 νm < Amax < 4.5 νm and 0.5 νm ≤ Bmax ≤ 4.5 <m. |