Electrochemical noise study on 2024-T3 Aluminum alloy corrosion in simulated acid rain under cyclic wet–dry condition
Electrochemical noise study on 2024-T3 Aluminum alloy corrosion in simulated acid rain under cyclic wet–dry condition
复制标题
DOI：
10.1016/j.electacta.2006.01.050
复制
发表时间：
2006-06
影响因子：
6.6
通讯作者：
Y. Shi;Zhao Zhang;Jingxin Su;F. Cao;Jian-qing Zhang
中科院分区：
文献类型：
--
作者：
Y. Shi;Zhao Zhang;Jingxin Su;F. Cao;Jian-qing Zhang
对2024-T3铝合金在不同pH值的模拟酸雨中进行了15次干湿循环的噪声试验。同时，还采用了动电位极化法和扫描电镜技术作为辅助手段。采用平均值、标准差和小波变换三种数学方法对记录进行分析。结果表明，每个干湿循环的阴极反应速率变化可分为3个区域，随着pH值的增加，主要阴极反应由质子的还原转变为氧分子的还原。EDP随时间的变化分析清楚地表明，整个腐蚀过程可以分为三个阶段的情况下，pH值为3.5和pH值为4.5和6.0的情况下，只有一个，这已经从理论上解释了根据腐蚀理论和实验的SEM证实。结果还表明，在pH 3.5的情况下的腐蚀比在pH 4.5和6.0的情况下更严重。这可能是由于氢离子比氧分子活泼得多的特性、氢离子在溶液中或通过表面膜的扩散/迁移速率高以及低pH值体系中表面钝化膜的稳定性差等因素的协同作用。
Potential noise records have been collected for 2024-T3 aluminum alloy, which was exposed to simulated acid rain with different pH value for 15 wet-dry cycles. Meanwhile, Potentiodynamic polarization and SEM techniques were also used as assistant measurements. Three mathematic methods including average, standard deviation and wavelet transformation have been employed to analyze the records. The results showed that each single wet-dry cycle can be divided into three regions with respect to the change of the cathodic reaction rate, and with the increase of pH value the main cathodic reaction changes from the reduction of protons to that of oxygen molecules. The analysis of the EDP versus time evolution clearly indicates that the whole corrosion process can be divided into three segments for the case of pH 3.5 and only one for the cases of pH 4.5 and 6.0, which have been theoretically interpreted according to the corrosion theory and experimentally proved by SEM. The results also showed that the corrosion in the case of pH 3.5 was much more rigorous than that in the cases of pH 4.5 and 6.0. It may due to synergistic effects of that, the characteristic of hydrogen ions which is much more active than that of oxygen molecules, the high diffusion/migration rate of hydrogen ions in solution or through surface films and the lower stability of surface passive film at low pH value system.