Abstract: The effect of Cl－ on the corrosion behavior of copper electrode in weak-alkaline medium was studied by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), in-situ ellipsometry and electrochemical impedance spectroscopy(EIS). The results showed that Cl－ had remarkable influence on the corrosion behavior of copper. The corrosion current of copper electrode in solution with Cl－ was about 10 times larger than that without Cl－. It was due to the decrease of the corrosion resistance of the film because the film was doped by Cl－ ion. The ellipsometry results not only were in good agreement with the electrochemical and XPS measurements qualitatively, but also could be used to distinguish every stage of corrosion, such as the formation of Cu2O film, the Cu2O film doped by Cl－ ion, the formation of CuO, and so on. Moreover, based on reasonable models as well as optical results, the composition, thickness and refractive index of the surface film on the electrode could be calculated quantitatively, which would provide important evidences for the reaction mechanism studies.

Key words: Copper electrode, Cyclic voltammetry, Electrochemical impedance spectroscopy, Ellipsometry, Corrosion