Corrosion Protection of AA2024-T3 by Cerium Malate and Cerium Malate-Doped Sol–Gel Coatings

Abstract

Cerium malate (CeMal) was tested as a corrosion inhibitor for AA2024-T3 in this work. Corrosion inhibition on bare AA2024-T3 indicated that the inhibiting effect was a result of the synergistic effect of cerium cations and maleic anions. The corrosion of AA2024-T3 was stagnated by greatly reducing the corrosion current when CeMal was present in NaCl solutions. CeMal was adsorbed on the surface of AA2024-T3 forming a protective film in the initial stage. Then, cerium cations transformed to cerium oxide/hydroxides, precipitating on the cathode sites to inhibit the further corrosion. The electrochemical impedance spectra results of the sol–gel coatings proved that CeMal was an effective corrosion inhibitor in the sol–gel coatings to provide corrosion protection for AA2024-T3.