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.