Patent ID: 8119227

Claim:
A cutting tool comprising a substrate of cemented carbide, cermet, ceramics, cubic boron nitride or high speed steel on which at least on the functioning parts of the surface thereof a thin, adherent, hard and wear resistant coating is applied, wherein said coating comprises a laminated multilayer of alternating PVD or PECVD metal oxide layers, Me 1 X+Me 2 X+Me 1 X+Me 2 X . . . , where the metal atoms Me 1 and Me 2 are one or more of Ti, Nb, V, Mo, Zr, Cr, Al, Hf, Ta, Y and Si, where at least one of Me 1 X and Me 2 X is a metal oxide+metal oxide nano-composite layer composed of two components, component A and component B, with different composition and different structure which components comprise a single phase oxide of one metal element or a solid solution of two or more metal oxides, wherein the layers Me 1 X and Me 2 X are different in composition or structure or both and have individual layer thicknesses larger than about 0.4 nm but smaller than about 50 nm and where said laminated multilayer has a total thickness of between about 0.2 and about 20 μm and wherein the laminated multilayer has a compositional gradient, with regard to a concentration of one or more of the metal atom(s), in a direction from an outer surface of the coating towards the substrate, the gradient being such that a difference between an average concentration of an outermost portion of the multilayer and an average concentration of an innermost portion of the multilayer is at least about 5 at-% in absolute units.