The electrochemical corrosion activities of 2xxx series Al alloys were investigated in NaCl of 0.3 M, and 0.6 M concentrations and seawater environments. Both Tafel polarization and electrochemical impedance spectroscopy (EIS) methods were followed to analyze the corrosion behavior. These results implied that corrosive attack is more aggressive in sodium chloride solution compared to seawater, as additional elements present in seawater are involved in forming various protective layers. Again, a higher concentration of NaCl solution damaged the alloy surface more drastically. The open circuit potential moved towards the nobler direction in the case of seawater environment, and 0.3 M solution for NaCl. The corrosion rate and corrosion current showed higher values in NaCl solution than in seawater. The surface morphologies of the alloys were characterized not only with an optical microscope but with a scanning electron microscope also. The scratch marks from polishing were removed after corrosion. Extensive damage to the surface was found in the NaCl environment, where 0.6 M solution created the most damage, which is evident by both optical and scanning electron micrography. A higher level of pitting corrosion occurred in NaCl than in seawater, identified by SEM images.

中文翻译：

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2xxx系列铸造铝合金在0.3 M、0.6 M NaCl和海水环境中的电化学腐蚀性能研究

研究了2xxx系列铝合金在0.3 M和0.6 M浓度的NaCl以及海水环境中的电化学腐蚀行为。采用塔菲尔偏振法和电化学阻抗谱（EIS）方法来分析腐蚀行为。这些结果表明，与海水相比，氯化钠溶液中的腐蚀侵蚀更具侵蚀性，因为海水中存在的其他元素参与形成各种保护层。同样，较高浓度的 NaCl 溶液对合金表面的损伤更加严重。在海水环境和0.3 M NaCl溶液的情况下，开路电位向更高的方向移动。氯化钠溶液中的腐蚀速率和腐蚀电流均高于海水中的腐蚀速率和腐蚀电流。合金的表面形貌不仅用光学显微镜进行表征，还用扫描电子显微镜进行表征。抛光后的划痕在腐蚀后被去除。在 NaCl 环境中发现了表面的广泛损伤，其中 0.6 M 溶液造成的损伤最大，光学和扫描电子显微摄影都可以证明这一点。通过 SEM 图像识别，氯化钠中发生的点蚀程度高于海水中。