Corrosion and wear resistance behaviors of electroless Ni–Cu–P–TiN composite coating

Abstract

Composite coating of Ni–Cu–P alloys containing TiN particles was prepared by electroless technique based on the excellent wear resistance of TiN and better anti-corrosion property of electroless Ni–Cu–P alloys on carbon steel surfaces. Electrochemical method which uses Tafel polarization curves was carried out to study the corrosion performance of the coating. The results indicate that the anti-corrosion ability of the Ni–Cu–P–TiN composite coating (7.92 μA) is almost doubled compared with that of the as-coated Ni–P (13.60 μA). Furthermore, heat treatment results in first increase and then decrease in anti-corrosion ability. And the Ni–Cu–P–TiN composite coatings heat-treated for 40 min have maximum hardness of HV 960 and a self-corrosion current of 28.20 μA. The friction coefficient of electroless composite coatings was measured by end-facing tribometer. It is found that the friction coefficient of the Ni–Cu–P–TiN composite coating decreases apparently compared with those of Ni–P and Ni–Cu–P electroless coatings.