Abstract: The present invention relates to CVD-coated cemented carbide tool used for chip forming machining. More particularly, it relates to a coating with an intermediate layer acting as a diffusion barrier thus influencing the coating structure and coating adhesion of the following layer.

Abstract: A method of coating a body coated with refractory single- or multi-layers, wherein specific layers are characterized by a controlled microstructure and phase composition with crystal planes preferably grown in a preferential direction with respect to the surface of the coated body. The coating comprises one or several refractory layers of which at least one layer is a dense, fine-grained layer of .alpha.-Al.sub.2 O.sub.3 preferably textured in the (012) direction. The coated tool according to the present invention exhibits excellent surface finish and shows much improved wear and toughness properties compared to prior art objects when used for machining steel, cast iron and, particularly, when machining nodular cast iron.

Abstract: A coated cutting tool body is coated with one or several refractory layers of which at least one layer is a dense, fine-grained layer of .alpha.-Al.sub.2 O.sub.3 preferably textured in the (012) direction. The coated tool according to the present invention exhibits excellent surface finish and shows much improved wear and toughness properties compared to prior art objects when used for machining steel, cast iron and, particularly, when machining nodular cast iron.