Comparison between the inhibition efficiencies of Ce(III) and Ce(IV) ammonium nitrates against corrosion of AA2024 aluminum alloy in solutions of low chloride concentration

► Comparison between Ce(III) and Ce(IV) salts as inhibitors of AA2024 corrosion. ► Both of cerium salts could react as corrosion activators or inhibitors as well. ► Oxides/hydroxides formed during inhibition by Ce(III) cover all cathodic sites. ► Ce(III) deposits contain Ce3+ and Ce4+ species but these of Ce(IV) have only Ce3+. ► The inhibition efficiencies of Ce(III) solutions are higher than those of Ce(IV).