5383铝合金与907钢和铝青铜早期电偶腐蚀的平面分布

Early Stage Galvanic Corrosion of 5383 Al Alloy Coupled with 907 Steel and Aluminum Bronze in 3.5%NaCl Solution

通过电偶电流测试和腐蚀形貌观察等方法,研究了5383铝合金分别与907钢和铝青铜组成的两种电偶体系的早期电偶腐蚀平面分布。研究结果发现,两种电偶对中5383铝合金为阳极,907钢和铝青铜则始终为阴极受到保护;5383铝合金的腐蚀形貌有亚稳点蚀、不规则点蚀和类丝状腐蚀;电偶电流随时间变化规律相似,即腐蚀初期电流迅速降低,之后趋于稳定;与偶接点的距离增大,电偶电流降低,且远端的电流分布较为均匀;5383铝合金与907钢偶接时比与铝青铜偶接时大部分区域电流密度更小,但电偶腐蚀更加集中于2 mm内的区域。

Galvanic corrosion performance of 5383 Al alloy coupled with 907 steel and aluminum bronze respectively in the early stage was studied by galvanic current test and scanning electron mi- croscopy （SEM）. The results showed that the 5383 Al alloy acted as anodes for the two galvanic couples, while 907 steel and aluminum bronze were cathode. The corrosion morphology of 5383 Al alloy could be metastable pitting, irregular stable pitting and filiform-like corrosion. The galvanic current density/g of two couples varied similarly with immersion time, they decreased at the begin- ning and then became stable. The galvanic current density decreased with the increase of distance from the couple joint, and it became uniform in the far end. Compared with the couple 5383 Al al- loy/aluminum bronze, the galvanic corrosion for couple 5383 Al alloy/907 steel was less severe, but it was more concentrated with in an area of 2 mm nearby the joint line.