用SEM研究氯离子对铁的钝化膜的作用

SEM Investigation into the Effect of Chloride Ions on the Iron Passive Film

利用扫描电子显微镜（ＳＥＭ）研究酸性溶液中氯离子对铁钝化过程的作用，ＳＥＭ实验结果表明：氯离子破坏了在铁的阳极钝化区域内形成的钝化膜，并引起孔蚀；硝酸根离子能够抑制氯离子引起的孔蚀，并使铁恢复钝化状态。这些实验结果与电化学方法获得的结果相一致．

The present work uses the scanning electron microscope (SEM) to investigate the effect of chloride ions on the iron passsivation in acidic medium. Results from the study reveal that chloride ions destroy the passive films in the anodic passive region of iron and cause pitting. On the other hand,nitrate ions are able to inhibit the pitting induced by chloride and to recover the passivity of iron. These results are in agreement with those obtained by the electrochemical methods. SEM is a useful tool that may further elucidate and explain the nature of passive films on iron.