Comparison of corrosion resistance of electrodeposited pure Ni and nanocrystalline Ni-Fe alloy in borate buffer solution

The corrosion resistance of electrodeposited pure Ni and Ni-Fe alloy in borate buffer solution was investigated. The electrochemical tests showed that Ni-Fe alloy had higher corrosion resistance than pure Ni. The Mott-Schottky analysis showed that iron oxides induced n-type semiconductor characteristic. Compared with pure Ni, the Ni-Fe alloy with finer grain size facilitated to form thicker and more compact passive films, which significantly improved the corrosion resistance of the Ni-Fe alloy in borate buffer solution. This was mainly attributed to the fact that more nanocrystalline boundaries in Ni-Fe alloy promoted the diffusion of nickel and iron. In addition, XPS analysis also showed that more hydroxides should be responsible for the degradation in the corrosion resistance of pure Ni.