Corrosion behavior of 2A12 aluminum alloy in Cl^- containing solution

The corrosion laws and electrochemical behaviors of 2A12 aluminum alloy in Cl^- containing solution were investigated by using immersion test. The microstructures and morphologies of corrosion products were observed and the corrosion dynamic law as well as the electrochemical behavior was also studied. The results showed that the obvious pitting and exfoliation corrosion occurred for specimens after 480 h immersion. The chloride ions and second phases were the mainly reasons to promote the occurrence and development of pitting corrosion. The kinetic for 2A12 aluminum alloy in NaCl solution complied with power rule according to weight loss measurements. Nyquist curves consisted of double capacitance arcs. With the extension of immersion time, pitting occurred, developed and peeled off, which made the change of impedance sequence decreased, increased and decreased agian.