Long-Term Corrosion Behavior of Cu-10Ni and Cu-20Ni Alloys in Simulated Seawater

This study investigates the long-term corrosion resistance of Cu-10Ni and Cu-20Ni alloys in simulated seawater. Weight loss tests, electrochemical impedance spectroscopy, and linear polarization resistance tests were conducted to evaluate the corrosion behavior of the alloys for 300 days with 30-day intervals. The results indicate that the Cu-20Ni alloy exhibits superior corrosion resistance to the Cu-10Ni alloy due to the higher electron work function and better protective properties of the oxide formed on its surface. Pitting corrosion occurred in both alloys, with the Cu-10Ni alloy displaying a higher corrosion rate. The results showed fluctuation in polarization resistance in both alloys with time which was due to the creation and transformation of passive films on the surface of the alloy, which can destabilize and deteriorate with time. It was found that the corrosion resistance of copper-nickel alloys can vary based on their composition and the environmental circumstances, and the establishment of a consistent and effective passive film is vital in augmenting their corrosion resistance.