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

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 microscopy(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 Igof two couples varied similarly with immersion time, they decreased at the beginning 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 alloy/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.