Exfoliation corrosion behavior of Al-Cu-Mg alloys for aerospace applications

The exfoliation corrosion susceptibility and electrochemical impedance spectroscopy (EIS) of Al-Cu-Mg alloys with different corrosive grades were studied to analyze the dynamic process of exfoliation corrosion by TEM and electrochemical. The results show that 2524-T4 aluminum alloy is good in exfoliation corrosion property, Cu-rich particles are the main influence factor of exfoliation corrosion behavior of the alloy, pitting corrosion occurs after 2d and light exfoliation corrosion can be found after 4d. Using EIS and equivalent circuit to analyze the corrosion dynamic process, the corrosion process includes formation of pitting corrosion, development of pitting corrosion, and formation of exfoliation corrosion. The interface reaction in the corrosion process contains dissolution of oxide film, formation, adsorption and exfoliation of surface corrosion products.