摘要
通有含溴离子氮气的３０４ Ｌ不锈钢管，经一段时期的使用后产生了严重点蚀。通过解剖被蚀钢管，采用金相分析，ＳＥＭ 形貌分析及ＥＤＳ成分分析的方法，对本案例点蚀特征进行研究， 发现：蚀孔形核于晶界，并以蚀孔自身扩张和孔内形成次生蚀孔两种方式生长，且蚀孔内壁产生富Ｃｒ 层。最后，就相关的电化学理论进行了探讨，并推测活化态蚀孔内壁的溶解导致了富Ｃｒ 层的产生，而富Ｃｒ 层的存在则是孔内建立局部活化态，次生蚀孔形核的物质基础。
Pitting corrosion was found on the inner surface of 304L stainless steel pipes, which was exposed to nitrogen gas containing bromine ions. Through metallographic analysis, SEM morphology analysis, and EDS analysis, pitting corrosion behavior of 304L stainleess steel had been studied. It had been discovered that pits nucleate on grain boundaries, and develop in two different ways, such as the growth of original pits and the nucleation of secondary pits on the wall of original pit. In addition, the pit wall had been found enriched in chromium and depleted in nickle and iron. Finally, this paper had discussed the relative electrochemical theroy, and proposed a model that the chromium rich passive film was the result of metal dissolve inside pit and results in the localized active state inside pit and nucleatiion of secondary pits on the wall of original pit.
出处
《南京化工大学学报》
1999年第6期26-30,共5页
Journal of Nanjing University of Chemical Technology(Natural Science Edition)
关键词
304L不锈钢
溴离子
点蚀
富铬层
孔内局部活化
304L stainless steel bromine ion pitting corrosion chromium rich passive film localized active state inside pit
