薄液膜下铝合金与不锈钢电偶腐蚀研究  

Study on the Galvanic Corrosion of Aluminium Alloy and Stainless Steel under a Thin Electrolyte Film

作　　者：刘艳洁[1] 王振尧[1] 柯伟[1] 

机构地区：[1]中国科学院金属研究所,沈阳110016

出　　处：《装备环境工程》2015年第1期1-5,24,共6页Equipment Environmental Engineering

基　　金：国防技术基础项目(H102011B002)~~

摘　　要：目的研究与不锈钢偶接时铝合金的腐蚀行为与机理。方法依据ASTM G149标准制备电偶试样,在循环盐雾箱中模拟薄液膜下2024铝合金与316L不锈钢之间的电偶腐蚀过程,分别在腐蚀6,12,18,24,30 d后取出试样,进行质量损失分析、截面与点蚀坑形貌分析、以及电化学阻抗谱测试。结果偶接之后2024铝合金的质量损失量是非偶接条件下的将近10倍。偶接后2024铝合金在腐蚀6 d后就形成了约20μm厚的腐蚀产物层,且随着腐蚀时间的增加,腐蚀产物层越来越致密,越来越厚。偶接后点蚀坑则主要在横向扩展,在纵深方向扩展较小。结论电偶作用不仅加速了铝合金的腐蚀,还改变了其腐蚀过程,而且这种作用在腐蚀的初期不明显,在腐蚀后期较为显著。Objective To study the galvanic corrosion behavior and mechanism of aluminium alloy coupled with stainless steel. Methods Galvanic samples were prepared according to the ASTM G149 standard, and the galvanic corrosion process between the 2024 aluminium alloy and the 316 L stainless steel under the thin electrolyte film was simulated in a cyclic corrosion tester. Samples were taken out after 6, 12, 18, 24 and 30 d of corrosion. Mass loss analysis, morphological analysis of sections and pits, as well as electrochemical impedance spectroscopy were used to analyze the corroded samples. Results The mass loss of 2024 AA coupled with 316 L SS was about 10 times that of the mass loss of 2024 AA without coupling. A corrosion product layer with a thickness of about 20 μm was formed on the coupled 2024 AA after 6 d of corrosion, and the corrosion product layer became more and more thick and compact with the corrosion time. The area of pits on the coupled 2024 AA was increased, while the depth varied to a smaller extent.Conclusion Galvanic corrosion did not only promote the corrosion of 2024 AA,but also changed the corrosion process.And the effects were much more obvious at the later stage of the corrosion than the initial stage.

关 键 词：铝合金 不锈钢 电偶腐蚀 形貌分析 电化学阻抗谱 

分 类 号：TJ011[兵器科学与技术—兵器发射理论与技术] TG172.3[金属学及工艺—金属表面处理]