Effect of Bath Compositions on the Properties of Electroless Ni-Cu-P Alloys on Aluminum

Abstract

In this work, the electroless plating Ni-Cu-P on aluminium is obtained successfully by direct Ni-Cu-P plating method. The effect of bath compositions on the electroless plating rate and the properties of the electroless Ni-Cu-P deposits was studied by orthogonal test. The corrosion resistance, hardness, surface morphology and components of the coating were studied by using electrochemical workstation, digital micro-hardness SEM and EDS. The optimum bath formula obtained is 0.6g/L copper sulfate, 30g/L nickel sulfate, 35g/L sodium citrate, 25 g/L sodium hypophosphite, 20g/L acetic anhydride and right amount of self-made additive. The deposition rate, hardness and corrosion resistance are all good. The adhesion between the deposits and the matrix is better. The deposits is smooth and uniformity, smooth by SEM. The deposit contains Ni 78.90%, Cu 8.65%, P 12.46% by the analyses of energy disperse X-ray.