纯镁在中性1．0mass％NaCl溶液中的腐蚀行为研究

CORROSION BEHAVIOR OF PURE MAGNESIUM IN NEUTRAL 1.0mass.% NaCl SOLUTIONS

以中性1.0mass% NaCl溶液为研究体系,通过电化学阻抗(EIS)结合形貌分析研究了纯镁的腐蚀发展过程及其腐蚀机理.结果表明:该腐蚀过程可被分为典型的三个阶段,分别为腐蚀初期点蚀的产生与发展、氧化膜在阳极表面的堆积以及腐蚀后期氧化膜的破裂造成新的阳极区域的出现;随着腐蚀程度的逐渐深入,电极表面的粗糙度在不同阶段也有相应的增加;腐蚀过程中EIS分形维数的变化趋势与腐蚀形貌之间有良好的对应关系.

The corrosion process of pure magnesium in neutral 1.0 mass. % NaCl solutions was investigated using electrochemical impedance spectroscopy （EIS） in conjunction with scanning electron microscopy （SEM） techniques. EIS allied with SEM and other electrochemical techniques in these experiments clearly demonstrated the influence of immersion time on the development process of corrosion. During the whole corrosion period, two time constants were confirmed by EIS plots, the high frequency one originates from the protective layer. The fractal dimension obtained from the time records of EIS seems to be a promising tool to analyze the corrosion morphology and metal surface.