Electrochemical and corrosion behaviors of pure Mg in neutral 1.0% NaCl solution

The corrosion behaviors and corresponding electrochemical impedance spectroscopy (EIS) and polarization curves of pure Mg in neutral 1.0% NaCl solution were investigated. The fractal dimension of EIS at different time was studied. The corrosion process and EIS evolution are divided into three stages. In the initial stage, EIS is composed of two overlapped capacitive arcs, the polarization resistance and charge transfer resistance increase rapidly with immersion time, and the corrosion rate decreases. Then, two well-defined capacitive arcs appear, and the charge transfer resistance and corrosion rate remain stable. After a long immersion time, inductive component appears in a low frequency range, the charge transfer resistance decreases and the corrosion rate increases with the immersion time. The fractal dimension obtained from the time records of EIS seems to be a promising tool for the analysis of corrosion morphology because of its direct relationship with the metal surface.