Patent ID: 8206812

Claim:
A coated cutting tool for metal machining comprising a body of cemented carbide or cermet onto which is applied a PVD coating wherein said coating has a thickness of from about 2.0 to about 20 μm, and comprises: a first (Me c1 ,Me c2 )(C,N,O) layer, c, where one or more of the elements C, N and O are present, Me c1 and Me c2 being different elements, and where Me c1 is one or more of the elements in the transition metal group IV-VI, Al and Si and Me c2 is one of the elements in the transition metal group IV-VI and Y having a thickness of from about 1.0 to about 4.5 μm, a second (Me d1 ,Me d2 )(C,N) layer, d, where one or more of the elements C and N are present, Me d1 and Me d2 being different elements, and where Me d1 is one or more of the elements Al, Zr, V, Nb, Si or Ti and Me d2 is one of the elements Zr, V, Nb, Y or Ti and Y having a thickness of from about 0.5 to about 4.5 μm and in between the first layer, c, and the second layer, d, an (Me e1 , Me e2 )(C,N,O) layer, e, where Me e1 is optionally present and one or more of the elements C, N and O are present, Me e1 and Me e2 are different elements, the atomic fraction of Me e1 to Me e2 is 0 to about 0.3 and where Me e1 is one or more of the elements in the transition metal group IV-VI, Al and Si and Me e2 is one of the elements in the transition metal group IV-VI and Y having a thickness of from about 0.1 to about 1.0 μm, where the thickness of the layer, e, between the first layer, c, and the second layers, d, is less than about 0.5 times the thickness of thinnest of the first layer, c, and the second layer, d, where the layer, e, between the first layer, c, and the second layer, d, has a composition differing from the first layer, c, and the second layer, d, and wherein the first layer, c, is in direct contact with the layer, e, and the layer, e, is in direct contact with the second layer, d.