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

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 anticorrosion 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.