Characterization of pitting corrosion of 7A60 aluminum alloy by EN and EIS techniques  

7A60铝合金点蚀行为的电化学噪声和电化学阻抗谱表征(英文)

作　　者：王学慧[1,2] 王吉会[1,2] 付丛伟[2] 

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300072 [2]天津大学材料科学与工程学院天津复合与功能材料重点实验室,天津300072

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第12期3907-3916,共10页中国有色金属学报（英文版）

基　　金：Project(13JCZDJC29500)supported by the Key Project of Tianjin Natural Science Foundation,China;Projects(2011CB610505,2014CB046801)supported by the National Basic Research Program of China;Project(20120032110029)supported by the Specialized Research Fund for the Doctoral Program of Higher Education,China

摘　　要：The pitting corrosion behaviors of 7A60 aluminum alloy in the retrogression and re-aging （RRA） temper were investigated by electrochemical impedance spectroscopy （EIS） and electrochemical noise （EN） techniques, and the microstructure and the second phase content of the alloy were observed and determined by scanning electron microscopy （SEM） and energy dispersive spectrometer （EDS）. The results show that there exist two different corrosion stages for 7A60 alloy in 3.5%NaCl solution, and the corrosion process can be detected by the appearance of EIS spectrum with two capacitive time constants and the wavelet fractal dimension D extracted from EN. SEM and EDS results also demonstrate that severe pitting corrosion in 7A60 alloy is mainly caused by electrochemical active MgZn2 particles, secondly by Al2MgCu and Mg2Si. Al7Cu2Fe particles make little contribution to the pitting corrosion of 7A60 alloy.采用电化学阻抗谱(EIS)和电化学噪声(EN)方法研究回归再时效(RRA)热处理状态下7A60铝合金的点蚀行为,通过扫描电子显微镜(SEM)和能谱仪(EDS)观察和分析合金的组织和第二相颗粒成分。结果表明,7A60铝合金在3.5%Na Cl溶液中存在两个腐蚀阶段,并且可以用EIS出现两个电容时间常数的时间和由EN计算出的小波分形维数D的变化来表征。SEM和EDS分析结果表明,在7A60铝合金中,严重的点蚀主要是由阳极相Mg Zn2引起的,其次是Al2MgC u和Mg2Si相,Al7Cu2Fe相对7A60铝合金点蚀行为的影响不大。

关 键 词：7A60 aluminum alloy constituent particles pitting corrosion electrochemical impedance spectroscopy electrochemical noise wavelet fractal dimension 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG172[金属学及工艺—金属材料]