Effect of plasma treatment of copper on its corrosion behaviour in 3.5 % NaCl solution

The influence of plasma preoxidation treatment on the corrosion behaviour of copper in a 3.5 % NaCl solution was evaluated. The electrochemical techniques used included potentiodynamic polarization curves, electrochemical impedance spectroscopy and linear polarization resistance at 20, 40 and 60 °C. The results showed that the preformed oxides included both cupric (CuO) and cuprous oxides (Cu2O). Potentiodynamic polarization curves showed a reduction in the corrosion current density value by one order of magnitude in the plasma-oxidized specimens. However, for longer exposure times, the corrosion rates were higher for the plasma-oxidized specimens. Corrosion rates increased with an increase in the testing temperature. The corrosion mechanism was changed by the plasma treatment since it was under charge control for the as-received specimens, whereas a diffusion-controlled mechanism was active for the plasma-oxidized specimens at temperatures of at least 20 °C.