通过室内浸泡模拟实验方法,研究了2A12铝合金在含Cl-典型环境中的腐蚀行为与电化学规律.采用扫描电镜观察了试样的组织和腐蚀产物的微观形貌,并用能量色散谱（EDS）分析了腐蚀产物元素组成.采用失重法分析了2A12铝合金腐蚀动力学规律,并采用电化学阻抗技术分析了2A12铝合金腐蚀后的电化学行为规律.实验结果表明,浸泡480 h后,2A12铝合金发生了明显的点蚀和小片状剥蚀,Cl-和第二相是促进点蚀形成和发展的主要原因;浸泡480 h后的动力学规律遵从幂指数规律;电化学阻抗谱中的Nyquist曲线由压缩的双容抗弧组成,随浸泡时间的延长,点蚀不断生成并发展,与腐蚀产物的产生与剥落综合作用,使电化学阻抗模值呈先减小后增大再减小的动态变化.
The corrosion laws and electrochemical behaviors of 2A12 aluminum alloy in Cl-containing solution were investigated by using immersion test.The microstructures and morphologies of corrosion products were observed and the corrosion dynamic law as well as the electrochemical behavior was also studied.The results showed that the obvious pitting and exfoliation corrosion occurred for specimens after 480 h immersion.The chloride ions and second phases were the mainly reasons to promote the occurrence and development of pitting corrosion.The kinetic for 2A12 aluminum alloy in NaCl solution complied with power rule according to weight loss measurements.Nyquist curves consisted of double capacitance arcs.With the extension of immersion time,pitting occurred,developed and peeled off,which made the change of impedance sequence decreased,increased and decreased agian.
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