含氯离子硫酸铜溶液中铝表面的点蚀观察

Observation in the Pitting of Aluminum by Chloride Ions in Cu SO_4 Solutions

利用SEM辅以EDS分析,对铜-铝置换反应下铝的氯离子点蚀的过程进行了元素的分析及形貌上的观察。点蚀核处没有铜的析出,并且点蚀核外壳部分氧含量达到50%,铝含量仅有15%;而点蚀核破裂的内部铝含量达到54%,而氧含量下降到16%。对于点蚀孔则发现了铜仅集中分布在蚀坑的周围与内部的浅层区域,并且蚀坑内部发现了铝形成了近乎直角的规则交叉棱柱结构。参考以往的研究成果,在文章中对点蚀过程中的这一系列现象给出了初步的理论解释。

In Cu- Al replacement reaction,SEM,supported by EDS,was used to observe morphology and analyze elemental composition of pitting process caused by chloride in Cu SO4 solution. According to EDS results,copper didn＇t precipitate at pitting nuclear,and oxygen content of the shell of pitting nuclear was about 50%,it was higher than aluminum,which was only 15%. However,oxygen content of the crack of pitting nuclear was 16%,it was lower than aluminum,which was 54%. In terms of pitting holes,copper was found around holes＇ edge and at shallow layer in holes,and copper didn＇t exist at the deep part of holes. In addition,a kind of regular prism structure of aluminum was observed in pitting holes,angle between prisms was almost 90°. Referring to existing research results,preliminary explanation was given to thisphenomenon.