Abstract: The invention concerns an abrasion resistent coating for steel and a method which makes it possible to obtain such a coating.The coating comprises two surface layers. The first surface layer, the outer layer, is formed of the phase (Cr, Fe).sub.2 B and possibly the phase M.sub.23 C.sub.6, while the second surface layer, the inner one, is formed of the phase (Fe, Cr).sub.2 B. In order to obtain this coating, a boriding is effected on steels at a temperature less than or equal to 950.degree. C. for a period of time greater than or equal to four hours, followed by a chromizing at a temperature less than or equal to 950.degree. C. for a period of time greater than or equal to 10 hours.Application to all steels in order to increase their resistance to wear is possible.

Abstract: An object of the present invention is a method for the anti-wear treatment of the surface of steel parts having a carbon content of at least 0.15% and the coating obtained thereby. The method is characterized by the fact that an addition of sulfur, by depositing of a metal sulfide for example, and a vapor-phase chromizing are carried out in sucession on the surface to be treated.The coating obtained is characterized by the presence of a layer of chromium sulfide on the surface and by the partial recrystallization of the underlying M.sub.7 C.sub.3 chromium carbide layer.The invention can be applied to any moving mechanical system which is subject to abrasion. The invention has importance because it increases the resistance to wear and the life of the system treated while limiting the wear of the untreated opposing part as a result of friction.