SURFACE TREATMENT OF A METAL PART

A process for the surface treatment of a metal part comprises: exposing a surface (1) of the metal part to a stream of substantially spherical particles, so that any portion of said surface receives said particles along several primary incidences, the primary incidences of the particles on a portion of the surface being essentially distributed in a cone or a conical film which has an outer half apex angle between 10° and 45°, until a surface layer (3) of nanostructures having an average thickness of several tens of microns is obtained, the particles having a diameter of less than 2 mm and greater than 0.1 mm and being projected at a speed between 40 m/s and 100 m/s. A thermochemical treatment is then applied, in particular a low-temperature treatment of the nitriding type or a high-temperature treatment of the low-pressure carbonitriding type.