纯镁在1.O％NaCl中性溶液中的腐蚀与电化学行为

摘要

研究纯镁在1.0％ NaCl中性溶液中的腐蚀行为及其相应的电化学阻抗谱(EIS)和极化曲线,探讨不同时间段EIS的分形维数.结果表明,腐蚀过程及相应的EIS发展可分为3个阶段.初始阶段,EIS由2个重叠的容抗弧组成,相应的极化电阻及电荷转移电阻随着时间的延长而快速增加,而腐蚀速率则降低.而后,EIS图谱上出现2个容易辨认的容抗弧,电荷转移电阻及腐蚀速率基本保持稳定.长时间浸泡后,EIS图谱中低频部分出现感抗成分,电荷转移电阻降低,而腐蚀速率增加.EIS分形维数与材料表面形貌直接相关,将是分析腐蚀形貌极有用的工具.%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.