采用电化学测试和化学浸泡两种方法, 研究了超级13Cr不锈钢的临界点蚀温度, 并对其点蚀形貌进行了分析。结果表明, 电化学和化学浸泡法测定的超级13Cr钢的临界点蚀温度相差了4 ℃, 主要原因是FeCl3强烈的氧化作用促进了点蚀的发生。化学浸泡法主要适用对比评价几种材料的耐点蚀性能, 电化学测试则可准确描述点蚀形成的临界条件。当温度低于临界点蚀温度(CPT)时, 材料表面形成孔径小于30 μm的点蚀坑, 蚀坑处于亚稳态; 当温度高于CPT时, 为点蚀的发展提供了条件, 形成稳定的点蚀。

The pitting corrosion behavior of super 13Cr stainless steel was studied by electrochemical test and chemical immersion methods, and the pitting morphology was observed by SEM. The results show that there was a difference of 4 ℃ in the critical pitting temperatures of the super 13Cr stainless steel determined by electrochemical and chemical immersion methods. This is due to the promotion function of strong oxidation of FeCl3 in chemical immersion. Chemical immersion appraisal is mainly suitable for comparison of the pitting performance of several materials, whereas the electrochemical test can further describe the critical condition of pitting. Meta-stable pitting with a diameter less than 30 μm was formed on material surface just below the CPT, while stable pits could only be formed above the CPT.