Inhibition of AA2024-T351 Corrosion Using Permanganate

Abstract

The inhibition of corrosion on AA2024-T351 in NaCl solutions, mitigated by either in-situ permanganate ions (MnO4−) or permanganate pretreatment, was examined. Both room temperature pretreatment and solution phase additions were studied as a function of inhibitor concentration. The roles of the inhibitor during anodic and cathodic polarizations were investigated. Inhibition of corrosion at open circuit corrosion potential (OCP) under conditions where anodic and cathodic reactions are coupled was also examined. The oxidation states of the manganese oxides that contributed to protection were determined using potentiometric electrochemical reduction and in-situ Raman spectroscopy. The thermodynamics of the Mn-water system was also considered over a range of concentrations. Permanganate was shown to be both an anodic and cathodic inhibitor, and an inhibitor of copper replating at OCP.