Abstract: A blade member for cutting tools comprises a cermet substrate having on a surface thereof a reaction layer. The reaction layer is composed of carbo-nitride of at least two metals in groups IV.sub.A, V.sub.A and VI.sub.A, the metals including Ti. The reaction layer may be composed of oxy-carbo-nitride of the above metals. The reaction layer may consist of inner and outer layers, the inner layer being composed of carbo-nitride of the above metals while the outer layer is composed of oxy-carbo-nitride of the above metals. The blade members with the reaction layer exhibits excellent toughness, wear resistance and thermoplastic deformation resistance. There is also disclosed a process for producing the above blade member.

Abstract: A cutting tool or a wear-resistant mechanical part comprises: a substrate of WC, Co, TiC, and TaC with or without an inner coating layer of TiC, TiN or TiCN; an intermediate layer of a titanium oxycarbide formed on the surface of the substrate or the inner coating layer by carrying out a reaction thereon at a temperature of 800.degree. to 1,200.degree. C. of a halide of titanium, hydrogen, and carbon monoxide or carbon dioxide or a mixture thereof; and an outer coating layer of aluminum oxide formed on the outer surface of the intermediate layer. The thicknesses of the inner layer, the intermediate layer , and the outer coating layer are of the order of 0.5 to 20 microns, 0.5 to 20 microns, and 0.5 to 10 microns, respectively.