Ni-P Coating on Steel Support by Electroless Method

Abstract

The autocatalytic reduction method (electroless method) was applied to obtain the Ni-P layers with different P contents. Nickel sulfate was used as nickel ion source and as reducing agent the sodium hypophosphite. The surface morphology, microstructure, layers thickness and corrosion resistance in acidic and basic environment were analyzed. The research results show a strong connection between layer characteristics and process parameters: pH and temperature. The analyzed layers show a high stability in 10% NaOH solution and different corrosion rates in HCl solutions (1 N and 0.5 N) depending on the phosphorus content in the layer.