Cu-Ni合金海水暴露腐蚀产物AES和XPS深度剖析

THE DEPTH ANALYSES OF CORROSION PRODUCTS OF Cu-Ni ALLOYS EXPOSED TO SEAWATER

考察了两种 Cu-Ni 合金实际海水暴露不同阶段腐蚀产物膜的变化,应用 AES 和 XPS 进行深度剖析。结果表明,保护性腐蚀产物膜薄而均匀,且与基体结合牢固。在该膜外侧发现了 FeOOH,从而证实了 Fe 的氢氧化物在膜的表面偏聚的假设。作者提出该水合氧化铁通过阻止 Ni 的流失促进 Ni 在腐蚀层中富集。非保护性的腐蚀产物膜呈现明显的层状结构,疏松而且粘附性差。前一种膜借助于直接氧化方式形成,后者则是由溶解的物质沉淀和重新沉积途径形成的。

The corrosion product films of two kinds of Cu-Ni alloys exposed to seawaterfor various periods of time were investigated and further analysed by AES and XPS in depth.The results show that the protective corrosion product film is thin,uniform and adherent,in ad-dition FeOOH is found at the outside of the film,which confirms the hypothesis that ironhydroxide segregates at the surface of the film.The authors propose that the FeOOH promotesnickel enrichment in the corrosion layer by preventing nickel from running off.The corrosionproduct film without protectiveness is of layered structure,loose and bad adherent.The formerforms through direct oxidation and the latter forms by precipitation and redeposition from dis-solved species.