不锈钢及镍基合金在含溴醋酸中的点蚀行为

THE PITTING OF STAINLESS STEEL AND NICKELBASED ALLOYS IN ACETIC ACID SOLUTION CONTAINING BROMINE ION

采用动电位扫描对 ２５４ ＳＭＯ， Ｎｉｃｋｅｌ ２００和 Ｈａｓｔｅｌｌｏｙ Ｃ－２７６三种材料在含溴醋酸中的点蚀行为进行了研究，并采用 ＳＥＭ观察点蚀形貌，实验结果表明，这三种材料耐点蚀的顺序从低到高为： Ｎｉｃｋｅｌ ２００， ２５４ ＳＭＯ和 Ｈａｓｔｅｌｌｏｙ Ｃ－２７６．对于材料 ２５４ ＳＭＯ，在含有少量醋酸的情况下，［Ｂｒ－］的对数与其点蚀电位和保护电位里线性关系，而且它们的斜率相等．采用 ＸＰＳ对极化后的试样进行表面分析，发现 ＭｏＯ２， Ｃｒ２Ｏ３对材料起到了保护作用。

Pitting corrosion behaviors of 254 SMO, Hastelloy C-276 and Nickel 200 in 10% HAc solution containing 0.049 mol/LBr- ion have been investigated using the cyclic potentiodynamic anodic polarization technique. The order of pitting resistance is Hastelloy C-276, 254 SMO and Nickel 200. The morphology of the pits produced after anodic polarization treatments was inspected by scanning electron microscope (SEM). For 254 SMO, in the case small amount of HAc, the both relationships between the pitting potential, protective potential and the logarithm of Br- ion concentration are linear and parallel each other approximately. The chemical compositions of passive film on the surfaces of 254 SMO and Hastelloy C-276 are studied by XPS, and the results show that the element Cr and Mo play important roles in pitting resistance.