Study of electroless Ni–Cu–P coatings and their anti-corrosion properties

Copper content in electroless Ni–Cu–P alloy coatings mainly depends on pH, temperature and Cu2þ concentration in plating solution and has a significant effect on the corrosion resistance of the coatings. In this paper, the effects of pH, temperature, Cu2þ concentrations and substrate materials on the deposition rate and the coating compositions were studied. The coating thickness and their compositions were measured using a digital micrometer and an energy dispersive X-ray microanalysis (EDX), respectively. The anti-corrosion properties of the Ni–Cu–P coatings in HCl and NaCl solutions were investigated. The results showed that the corrosion resistance of the Ni–Cu–P alloy coatings was superior to that of electroless Ni–P coatings or copper. The optimal conditions for preparing these corrosion-resistant Ni–Cu–P coatings were obtained. # 2004 Elsevier B.V. All rights reserved.