(北京科技大学 腐蚀与防护中心，北京 100083)
摘 要: 通过盐雾腐蚀试验模拟研究7A04铝合金在海洋大气环境中的腐蚀初期规律，采用电化学交流阻抗测试和扫描Kelvin探针技术，研究7A04铝合金在初期腐蚀过程中的电化学行为。结果表明：Cl−对铝合金腐蚀有显著的加速作用，盐雾试验初期表面出现点蚀坑；随盐雾时间增长，点蚀相互连接并扩展，电化学反应阻抗下降。扫描开尔文探针测试结果表明：随腐蚀的不断进行，金属表面阴极区和阳极区不断发生变化，呈现局部腐蚀的特征，表面电位也随时间逐渐升高，阴极区和阳极区逐渐变得明显，腐蚀反应处于不断加速过程。
关键字: 7A04铝合金；大气腐蚀；电化学交流阻抗；扫描Kelvin探针
7A04 aluminium alloy in marine atmosphere
（Corrosion and Protection Center, University of Science and Technology Beijing, Beijing 100083, China）
Abstract: The initial corrosion of 7A04 aluminium alloy in marine atmosphere was studied. Salt fog test was used to simulate the marine atmospheric environment. Electrochemical impedance spectroscopy (EIS) and scanning Kelvin probe (SKP) were employed to investigate the electrochemical behavior of 7A04 aluminium alloy in marine atmosphere. The results show that the Cl− can accelerate the atmospheric corrosion of 7A04 aluminium alloy during the beginning exposure period. Pittings appear in the initial stage of salt fog test and link each other to expand with prolonging test time. The electrochemical impedance magnitude declines during the corrosion test. The SKP results indicate that the anodic and cathodic areas change constantly with distinct character of localized corrosion. When the corrosion process continues, the surface potential of 7A04 aluminium alloy increases, while anodic and cathodic area distinguish evidently from each other. Atmospheric corrosion of 7A04 aluminium alloy is promoted during the initial stage in marine air.
Key words: 7A04 aluminium alloy; atmospheric corrosion; EIS; SKP
