Insight to corrosion mechanism of 90/10 copper-nickel alloys under different sea depths

Abstract In this paper, for the first time, the corrosion behavior of 90/10 copper-nickel alloys was investigated systematically by simulating the different sea depths using static weight loss test, XPS depth analysis (argon ion etching), and electrochemical method. The static weight loss test showed that the average corrosion rate increased first, and then decreased with the increase of sea depth. XPS spectra demonstrated that the composition of the corrosion product layer did not change with variation of sea depth. The outer corrosion product was mainly CuO, Cu2O, Cu2Cl, NiO, and γ-FeOOH, while the inner corrosion product was mainly Cu2(OH)3Cl, Cu2O, NiO, Ni(OH)2, and γ-FeOOH. Electrochemical impedance spectroscopy exhibited that the inner corrosion layer played an important role in protecting the alloy.