In this study the microstructural characterization and the abrasion resistance of a series of Ni based alloys containing 10 at. % Cr, 5-15 at. % B and 5-20 at. % Si are presented. The formed hard components are borides of chromium and nickel (CrB, Cr5B3, Ni3B) and a silicon nickel compound (Ni5Si2) in a <Ni> matrix. These phases appear either in primary solid solution form or in biphased eutectic form or in secondary fine precipitates form. The loss of mass, the abrasion factor and the microhardness of the various phases versus time were measured. The best results are obtained for 10 at. % B and Si contents of about 10 at. %.