运用氧化-冷凝液蒸发循环方法模拟汽车消声器内腐蚀环境, 研究了409不锈钢在两种冷凝液中的腐蚀行为, 并分析了Cl-对冷凝液腐蚀的作用. 结果表明, 经250 ℃氧化后409不锈钢在冷凝液中表现出良好的钝态腐蚀性能, 但无论冷凝液中是否存在Cl-, 钝化膜在氧化和腐蚀的循环作用下均会被破坏而形成局部腐蚀坑.Cl-存在时, 蚀坑内不易形成保护性氧化膜, 形成的蚀坑更深.
The corrosion behavior of 409 ferritic stainless steel in two kinds of condensate solution with or without Cl- was investigated to analyze the corrosion effect of Cl- in condensate solution by applying cyclic oxidation-condensate evaporation method, which simulated the corrosive environment inside automotive exhaust mufflers. The results of electrochemical tests in both solutions showed that passive films formed first after oxidation at 250 ℃, then was deteriorated during the cyclic oxidation and evaporation process, forming pitting due to localized corrosion. However, the presence of Cl- in the solution retarded the formation of protective oxide film in the pits, and further promoted the growth of pitting.