Corrosion Resistance of Three Kinds of Ni-base Alloy Electroless Plating Layer

Three kinds of electroless Ni-P plating with high P content,Ni-W-P and Ni-W-P/Pr2O3 were prepared.The corrosion resistance of the three kinds of plating was compared using immersion experiment in 5% NaCl.The corrosion electrochemical behaviors in 3.5% NaCl solution of the three kinds of plating were tested by polarization curves.The results showed that the Ni-W-P/Pr2O3 plating was the best,and Ni-P film was the worst.The corrosion current densities of Ni-W-P and Ni-W-P/Pr2O3 platings were 3.863 μA/cm2 and 2.977 μA/cm2,much smaller than that of the Ni-P film,which was 10.11 μA/cm2.The ternary alloy plating have more excellent corrosion resistance than binary alloy plating.The corrosion resistance of ternary alloy plating could be improved by adding rare earth.The low porosity and easy passivation are the important reasons for high corrosion resistance.