Corrosion Inhibition of AA2024-T3 by Vanadates

Abstract

The speciation of vanadate solutions and the resulting inhibition of oxygen reduction and corrosion of AA2024-T3 were investigated. 51V NMR is very useful for assessing vanadate speciation. Clear metavanadate solutions contain no decavanadate, which forms whenever the pH was decreased by the addition of acid. Orange decavanadate solutions contain no monovanadate, even when the pH is adjusted to high values. Monovanadate is a potent inhibitor in contrast to decavanadate. Inhibition by monovanadate seems to result from an adsorption mechanism rather than reduction. Monovanadate effectively protects S phase particles. Aging of high-pH decavanadate solutions does not improve the inhibition performance or result in complete depolymerization of the decavanadate.