Abstract

Corrosion inhibition of aluminum alloy (AA)2024-T3 (UNS A92024) in sodium chloride (NaCl) solutions after pretreatments in solutions containing Ce(III), Co(II), or Mo(VI) ions are reported. The extent of Cu replating on AA2024-T3 surfaces and the reduction of the oxygen reduction reaction were utilized as key indicators of inhibitor potency. Critical inhibitor concentrations were determined independently for each inhibitor at several NaCl concentrations. Anodic inhibition by Mo(VI) addition and its critical anodic inhibitor concentration were also determined. The inhibition of oxygen reduction on AA2024-T3 by Ce(III), Co(II), Co(III), and Mo(VI) was observed. Subsequently it was demonstrated that the corrosion of AA2024-T3 in NaCl could be inhibited by the release of Co(II) and Ce(III) ions during exposure to a sacrificially corroding amorphous Al-Co-Ce alloy. This alloy served as a source of the same inhibitor ions as discussed above, and critical inhibitor concentrations of Co(II) and Ce(III) ions were obtained in a small volume cell. Hence, the active chemical inhibition of corrosion via an Al-Co-Ce metal coating serving as a source of inhibitor ions has been demonstrated.

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