Study on Corrosion Behavior and Mechanism of 5A06 Aluminum Alloy in N2O4 Medium

The corrosion behavior of 5A06 aluminum alloy in N2O4 was investigated to explore the influence of immersion time. The XPS results confirmed the existence of corrosion products N-H and nitrate after immersion in the N2O4 medium. Surface morphology analysis showed that the pitting mainly initiated around the intermetallic and their vicinity. The reason is the dissolution of the aluminum matrix around the intermetallic AlFeMn and the dealloying of magnesium in Mg2Si. The dissolution of the aluminum matrix near the AlFeMn precipitate and the dissolution of the AlMg precipitate lead to intergranular corrosion. Intergranular corrosion appeared after being immersed for three months and gradually developed into exfoliation corrosion. Eventually, the corrosion mechanism of aluminum alloy in the N2O4 system was discussed.