| 摘要 |
A coated hard metal which has high resistance against wear, chipping, welding, and flaking is offered. The coated hard metal is provided with an inner layer, intermediate layer, and outer layer on the surface of the hard metal. The inner layer includes a layer comprising at least one member selected from the group consisting of (a) the carbides, nitrides, borides, and oxides of the elements belonging to the IVa, Va, and VIa groups in the periodic table and (b) the solid solutions of these. The intermediate layer includes a layer comprising at least one member selected from the group consisting of aluminum oxide, zirconium oxide, and their solid solution. The outer layer includes a layer of titanium carbonitride having a columnar structure. In a cross section showing the structure of the coated hard metal, the relation between "Amax," which signifies the maximum roughness at the outer face of the intermediate layer, and "Bmax," which signifies the maximum roughness at the outer face of the layer of titanium carbonitride having a columnar structure in the outer layer, satisfies equation 1. <DF NUM="equation 1,">(Bmax/Amax) < 1 </DF> where 0.5 mu m < Amax < 4.5 mu m, and 0.5 mu m </= Bmax </=4.5 mu m. <IMAGE> |
