Enhancement of Wear and Corrosion Resistance of M2052 Damping Alloys by Electroless Plating Ni-P Coating

摘要

M2052 is a famous high damping Mn-Cu alloys with good strength, but lack of well corrosion and wear resistance. In this study, we expect to enhance the wear and corrosion resistance of M2052 damping alloys by electroless plating Ni-P coating. Successfully, a high phosphorus amorphous Ni-P coating with thickness about 15 μm plated on M2052 substrate. After electroless plating Ni-P coating, the roughness of samples surface decreased and the microhardness increased. Thus, the coated sample featured better wear resistance, and attributed to adhesive wear mechanism. By contrast, the friction coefficients of uncoated samples presented a high value with great fluctuations, which due to low hardness, high roughness, and easier to be oxidized. This leads to the dominant wear mechanisms are abrasive and corrosive wears. Ni-P coating significantly improved the corrosion resistance, because it has lower I_(corr), higher E_(corr), and higher impedance than M2052 substrate. Surface morphologies after electrochemical tests were also observed: the uncoated samples had been corroded severely with a fibrous corrosion product layer dispersing cracks and pits. However, coated samples had not been corroded and remains intact. Furthermore, Mott-Schottky plots inferred that the sample surface after plating Ni-P coating performed an excellent passivation behavior in NaCl solution.