Abstract The correlation between passive film and AC corrosion behavior of 2507 super duplex stainless steel (SDSS) has been investigated in NaCl solution under various AC current densities using the polarization curve, EIS test, Mott-Schottky curve and with immersion test. Additionally, the corrosion mechanism of passive film under AC interference was studied by X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). The test results indicate that the roughness of the passive film increases and the composition as well as electronic properties change under AC interference. Moreover, AC interference can enhance the dissolution of passive film, resulting in a non-uniform destructive effect to the film. The passivity of stainless steel degrades and pitting sensitivity increases as the increase of iAC. When iAC is less than 100A/m2, the pit initiation sites mainly concentrate on the austenite phase and the boundary between ferrite and austenite phase. However, a great number of pits occur on the ferrite phase while iAC equals to 200A/m2.

中文翻译：

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2507超级双相不锈钢在模拟海洋环境中钝化膜与交流腐蚀行为的相关性研究

摘要 采用极化曲线、EIS 试验、Mott-Schottky 曲线和浸泡试验研究了2507 超级双相不锈钢(SDSS) 在不同交流电流密度下NaCl 溶液中钝化膜与交流腐蚀行为的相关性。此外，通过X射线光电子能谱（XPS）和原子力显微镜（AFM）研究了交流干扰下钝化膜的腐蚀机理。测试结果表明，在交流干扰下，钝化膜的粗糙度增加，成分和电子特性发生变化。此外，交流干扰可以增强钝化膜的溶解，导致对膜的非均匀破坏作用。随着iAC的增加，不锈钢的钝化性降低，点蚀敏感性增加。当 iAC 小于 100A/m2 时，凹坑起始点主要集中在奥氏体相和铁素体与奥氏体相的边界处。然而，在iAC 等于200A/m2 的情况下，铁氧体相上出现了大量的凹坑。