Corrosion behavior of aluminium in ethyleneglycol-water electrolytes containing EDTA

The role of EDTA on the behavior of Al in ethyleneglycol-water media has been investigated through electrochemical and atomic force microscopy measurements. It has been found that, at open circuit potential (OCP), as compared to an aqueous solution of the same pH, the adsorption of EDTA on the surface of the Al electrode is favored in ethyleneglycol rich mixtures. In these solutions, the defects of the aluminium oxide film are repaired due to the adsorption of the ligand, giving rise to a more protective layer. Moreover, as compared to the oxide film grown in the absence of EDTA, the one grown in its presence shows greater uniformity and lesser porosity, remaining stable for longer immersion periods.