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The mechanisms of corrosion inhibition of AA2024-T3 by vanadates were studied using chronoamperometry, polarization curves and adsorption isotherms. The electrochemical behaviour of clear solutions containing metavanadates and orange solutions containing decavanadates was clearly distinctive. Metavanadates reduced the kinetics of oxygen reduction to an extent similar to chromates. Corrosion inhibition of AA2024-T3 by metavanadates was very rapid and it might occur by the formation of an adsorbed layer. Reduction of clear metavanadate solution was very slow. Approximately 35min were required to develop a monolayer of a reduced vanadate species. The adsorption of the inhibitor likely blocked reactive sites on intermetallic particles, discouraging the oxygen reduction reaction (ORR). Adsorption of the inhibitor on the Al matrix could also displace Cl⁻ ions, increasing the stability of the passive film …