Abstract: Spinodally-decomposing mixed crystals of zirconium and titanium carbides, possibly including carbonitrides and optionally including one or more carbides of metals of Group Vb of the Periodic Table of the Elements, are used in making sintered hardmetals based on tungsten carbide. One or more iron group metals or alloys, preferably cobalt or a nickel alloy, is or are used as a binder. The sintered hardmetals are made by a 2-stage process, mixed crystal material comprising zirconium and titanium carbides being formed in the first stage and being combined with the binder and tungsten carbide in the second stage. Process variations which encourage spinodal decomposition of the mixed crystal material are also disclosed.

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 polycrystalline diamond body infiltrated by a silicon atom-containing metal (e.g., silicon alloy) is bonded to a substrate comprising cemented carbide with a barrier of refractory material extending between the diamonds cemented together with silicon atom-containing binder and the substrate substantially precluding migration of the cementing medium (e.g., cobalt) from the carbide substrate into contact with the silicon atom-containing bonding medium in the diamond body. The process comprises subjecting a mass of diamond powder, a quantity of silicon atom-containing metal binder material, a cemented carbide body and a barrier made of material selected from the group consisting of tantalum, vanadium, molybdenum, zirconium, tungsten and alloys thereof to the simultaneous application of elevated temperature and pressure.

Abstract: An improved sintered cemented carbide body and method for making same is disclosed. The improved sintered cemented carbide body contains at least one metal carbide and a binder metal, on which body there is applied at least one thin, wear resistant surface layer consisting essentially of aluminum oxide and is characterized in that at least 85% of the aluminum oxide consists of the kappa form, the remainder, which mainly constitutes the alpha form, being formed as surface portions or spots having a size of at the most 10 .mu.m, .[.the size and the occurrence of the surface portions being so adjusted that they lie within the area AOB in FIG. 1 of the attached drawing..].The body is made by a method wherein a cemented carbide substrate is contacted with a gas containing an aluminum halide and a reducing agent at high temperature, characterized in that a dopant addition of tetravalent titanium, zirconium and/or hafnium ions is added to the gas in an amount of 0.03-0.5% of the totally supplied amount of gas.