Multilayer coated cemented carbides

Abstract

Multilayer coated cemented carbides excellent in wear resistance and toughness are provided comprising a substrate of cemented carbide, an inner layer contacted with the surface of the substrate, and an outer layer contacted with the inner layer, the inner layer being a single layer and/or laminated layers consisting of at least one member selected from the group consisting of carbides, nitrides, carbonitrides, carboxynitrides, oxynitrides, boronitrides and borocarbonitrides of Ti, and the outer layer being a multilayer with a total thickness of 5 to 20 .mu.m, consisting of a plurality of Al.sub.2 O.sub.3 layer each having a thickness of 0.01 to 2 .mu.m, each consisting of an Al.sub.2 O.sub.3 film in which titanium oxide is dissolved or at most 30 vol % of titanium oxide is coexistent and being respectively divided by interlayers each having a thickness of 0.01 to 2 .mu.m and each consisting of at least one member of the group consisting of TiC, TiN, TiCN, TiCNO, TiNO, Ti oxides Ti(B, N), Ti(B, N, C), SiC, AlN and AlON.

Dependencies are inferred from the claim text.