Investigation on the electrochemical behaviour of copper under HSO ₃ ^--containing Thin electrolyte layers

The electrochemical behaviour of copper under HSO ₃ ^--containing thin electrolyte layers (TEL) was investigated by using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electronic microscope (SEM). The results indicate that the corrosion potential of copper E _corr shifts to noble values in the presence of thinner TEL. The anodic current decreases, as the thickness of TEL decreases, indicating that the thin electrolyte layer can somewhat inhibit anodic corrosion rate. When the thickness of TEL under the 200 and 100 μm, special hump region appeared which involve some anodic reactions, in the very low overpotential during cathodic process. Moreover, the shape of corrosion products incline transfer from round and flat to irregular shape with thin electrolyte layers thickness increasing.