"A coated substrate product is described wherein the outer coating on the substrate is comprised of a chemically vapor deposited and heat treated mixture of tungsten and tungsten carbide. The tungsten carbide phase consists of W.sub.2 C or W.sub.3 C or a mixture of W.sub.2 C and W.sub.3 C. During the heat treating, the coated substrate is heated to the deposition temperature or not substantially above the deposition temperature in a non-reactive atmosphere. The heat treating temperature is sufficient to confer a desired improvement in erosive and abrasive wear resistance in the outer coating but does not result in substantial degradation of the mechanical properties of the substrate or in formation of undesirable inter-metallic layers".