Abstract: A method for the treatment of tungsten carbide is provided. The starting material contains tungsten carbide particles of a W—C system represented on a phase diagram showing a monophasic domain of a ? phase having a face-centered cubic structure, upwardly delimited by a liquidus line. The particles are subjected to a homogenization treatment in the monophasic domain, and may be subsequently melted to be spheroidized. They are then quenched to freeze at ambient temperature the monophased structure. Optionally, at least one alloying element may be added to the starting material to enlarge the monophasic domain, thereby increasing the hardenability of the monophased particles.

Abstract: The invention concerns a mechanical part with abrasionproof surface characterized in that it comprises a sintered metallic body obtained from metallic powders and a laser-deposited cermet coating. The coating has a certain thickness whereof a portion is metallurgically bound with the metallic body. The laser deposit enables the sintered part to be surface-melted under the effect of the laser beam. The surface of the sintered part to be coated is therefore fused over a thickness ranging between 10 &mgr;m and 1 mm, which enables the surface pores to be closed, as is characteristic of sintered parts, thereby increasing its resistance to shocks. Moreover, the small surface coated at a given moment by the laser enables the self-hardening of the exposed part, following the beam displacement, by the heat-sink effect of the surrounding metallic volume. The resulting coating also has very low porosity owing to the complete fusion of the powders by laser.