Abstract: Tungsten carbide tools are provided having improved wear properties which tools produce an improved surface finish on workpieces cut with said tools, both initially and after extended use. The tools are prepared by a process which comprises applying a coating of a Group IVB or VB metal of the Periodic Chart of the Elements over the tool, diffusing said metal into the tool and removing any excess of the metal from the surface of the tool, possibly by further diffusion of the metal into the tool. The preferred method is by gaseous decomposition of a metal halide in an atmosphere which does not contain a carbon source such as methane, used in some previous processes. The source of the carbon in the Group IVB or VB metal carbide is the carbon in the carbide tool being coated. Tools formed in accordance with the invention have wear properties such that they typically last at least four times as long as untreated tools and under most preferred conditions, as much as nine times as long as untreated tools.