AC impedance monitoring of pitting corrosion of stainless steel under a wet-dry cyclic condition in chloride-containing environment
AC impedance monitoring of pitting corrosion of stainless steel under a wet-dry cyclic condition in chloride-containing environment
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DOI：
10.1016/0010-938x(96)00028-5
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发表时间：
1996-08
影响因子：
8.3
通讯作者：
R. Cruz;A. Nishikata;T. Tsuru
中科院分区：
文献类型：
--
作者：
R. Cruz;A. Nishikata;T. Tsuru
本文用交流阻抗法研究了不锈钢在干湿循环条件下的腐蚀。将三种类型的不锈钢暴露于在含氯化物溶液中浸泡1小时并在25 °C和60%RH下干燥5小时的交替条件下。在暴露过程中使用交流阻抗监测技术连续监测腐蚀速率。同时，在阻抗测量期间，从中频中的相移θ分析工作电极上的电流分布。结果表明，在给定的暴露条件下，即使在干燥期间，当金属覆盖有薄的电解质层时，使用交流阻抗法的腐蚀速率监测是可能的。从阻抗监测数据可以区分钝化、点蚀和再钝化的不同过程。结果发现，在含氯化物的环境中的干湿循环条件下，凹坑的产生和生长优选地恰好在金属表面的完全干燥之前发生，并且再钝化优选地在表面干燥并重新浸入溶液中时发生。
A study of the corrosion of stainless steels under a wet-dry cyclic condition has been carried out using the AC impedance method. Three types of stainless steel were exposed to the alternate conditions of 1 h immersion in chloride containing solution and 5 h drying at 25 °C and 60% RH. The corrosion rates were monitored continuously during exposure using an AC impedance monitoring technique. Simultaneously, the current distribution over the working electrode during impedance measurement was analysed from the phase shift Θ in an intermediate frequency. The results showed that corrosion rate monitoring using an AC impedance method is possible under the given exposure conditions even during the drying period when the metal is covered with a thin electrolyte layer. The different processes of passivation, pitting corrosion and repassivation could be distinguished from the monitored impedance data. It was found that in the wet-dry cyclic condition in the chloride-containing environment, pit generation and growth occur preferably just before the perfect drying of the metal surface, and repassivation occurs preferably when the surface dries out and is re-immersed in the solution.