通过干湿周浸试验、扫描电镜观察和电化学阻抗谱(EIS)测试, 研究了2A12铝合金在不同质量浓度NaCl溶液中干湿周浸48 h和480 h后带锈样的电化学行为与规律。试验结果表明, 干湿周浸48 h后, 低浓度NaCl溶液中2A12铝合金的腐蚀过程主要受电荷转移电阻控制; 随浓度增加, 其电化学特征转变为受电荷转移电阻和Warburg阻抗扩散混合控制。干湿周浸480 h后, 0.5%和10% NaCl溶液中2A12铝合金的Nyquist曲线由高频容抗弧和中低频扩散阻抗组成, 而2.5%至5%浓度的Nyquist曲线由高低频双容抗弧组成。提高Cl-浓度可以促进点蚀的形成和发展, 进而影响电化学行为。

The electrochemical behaviors of aluminum alloy 2A12 was investigated using alternate immersion test, scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) techniques. The results showed that the corrosion process was mainly controlled by charge transfer resistance under the condition of lower Cl- concentration after 48 h alternate immersion; with increasing the Cl- concentration, the electrochemical characteristic changed to mixed control of charge transfer resistance and Warburg resistance. After 480 h alternate immersion, Nyquist curves consisted of capacitance arc at high frequencies and Warburg impedance at low frequencies in 0.5% and 10% NaCl solutions, but changed into two capacitance arcs in 2.5% to 5% NaCl solutions. The increase of Cl- concentration could promote the formation and propagation of pitting, and thus the electrochemical behavior of 2A12 aluminum alloy was affected.