铝合金表面电偶腐蚀与电子功函数的关系  

Correlation between Galvanic Corrosion and Electronic Work Function of Al Alloy Surfaces

作　　者：王健[1,2,3] 王绍青[1] 

机构地区：[1]中国科学院沈阳金属研究所,沈阳材料科学国家(联合)实验室,沈阳110016 [2]中国科学技术大学化学与材料科学学院,合肥230026 [3]辽宁科技大学理学院,辽宁鞍山114051

出　　处：《物理化学学报》2014年第3期551-558,共8页Acta Physico-Chimica Sinica

基　　金：国家重点基础研究发展规划项目(973)(2011CB606403)资助~~

摘　　要：铝合金中经常会引入一些第二相来改善其性能,第二相由于和铝基体的电位差不同,将会对铝合金的局部腐蚀产生重大的影响.为了揭示铝合金腐蚀的物理本质,本文利用基于密度泛函理论第一性原理的计算方法,详细计算了铝合金中一些主要第二相(Al_2Cu、Al_3Ti和Al_7Cu_2Fe)的多种晶面的电子功函数,分析了电子从各个晶面逸出的难易,求得了第二相与Al基体的本征电势差,我们发现不同的晶面暴露在合金最外层,会显著地影响本征电势差;即便是同一晶面,暴露在最外层的原子种类和构型不同,对腐蚀的影响也不一样.从电子的层面解释了电偶腐蚀发生的原因.Al al oys contain some secondary phases to improve their properties. These secondary phases have different potentials to the Al matrix, which greatly affect the localized corrosion of Al al oys. In order to reveal the physical nature of Al al oy corrosion, we use the first-principles method based upon density functional theory to calculate the work function of the main secondary phases （Al2Cu, Al3Ti, and Al7Cu2Fe）. The difficulty of electrons escaping from various crystal planes was analyzed, and the potential difference between the secondary phases and Al matrix was obtained. We find that different crystal planes exposed to the outmost layer significantly impacted on the potential difference. Different atomic types at the outmost layer play different roles in Al al oy corrosion, even for the same crystal surface. The causes of galvanic corrosion were thus revealed.

关 键 词：铝合金 第二相 电子功函数 电偶腐蚀 第一性原理 

分 类 号：TG146.21[一般工业技术—材料科学与工程]