Corrosion and passivation behavior of 6082‐T6 aluminum alloy in NaCl solution

Abstract The corrosion and passivation behaviors of 6082‐T6 aluminum alloy in 1.5 wt% NaCl solution with natural aeration were investigated by segmented electrochemical measurement combined with scanning electron microscope, transmission electron microscope, and X‐ray diffractometer. The results showed that the active Mg dissolved from Mg 2 Si promoted the development of intergranular corrosion (IGC) and that local dissolutions of the matrix around the Si and AlFeMnSi particles are the initial sites for pitting corrosion. The passivation overlying the IGC crack is interacted by the cations in the layer and the ions, resulting in the intergranular cracking of the passive film. The cracks near the secondary phase meet the cracks developing along the grain boundary, resulting in the failure of the passive film in the form of networks.