Electroless deposition of ternary Ni–P alloy coatings containing tungsten or nano-scattered alumina composite on steel

The performance of ternary electroless deposited Ni–P–W and Ni–P–alumina composite coatings on low carbon steel substrates was studied. The effect of experimental parameters, such as temperature, pH, nickel sulfate concentration, sodium hypophosphite concentration, sodium citrate concentration, and deposition time on the deposition rate were investigated. The coating brightness, coherence, and uniform surface distribution were improved due to addition of W and alumina. The coating performance was evaluated based on the wear-resistance, micro-hardness, and corrosion resistance. The Ni–P–W ternary alloy coatings showed the highest micro hardness, wear-resistance, brightness, and corrosion resistance. The improvement in the performance of Ni–P–W coatings can be explained by the formation of a tungsten phosphide phase.