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 (MnO 4 − ) 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.

Steam assisted oxide growth on aluminium alloys using oxidative chemistries: Part II corrosion performance

“…However, significant amount of MnO 4 − was not detected, which is essential for superior corrosion protection due to the possibility of reducing MnO 4 − into lower valence state to inhibit corrosion. Moreover, if MnO 4 − is present in the coating in ionic form it may reduce to lower valence compounds and act as additional cathodic reactants [43]. Bibber [44,45] reported high filiform (on powder coated samples) and salt spray corrosion resistance for permanganate conversion coated AA6061 at ∼66 • C followed by a sealing step unlike the results obtained in the present investigation.…”

Mitigation of corrosion challenges for barrier films at advanced nodes

“…In the alkaline region in the presence of KMnO4 four cathodic reactions, oxygen reduction (reaction 6) and the three permanganate ion (MnO 4 -reduction reactions (reaction7, 8 and 9) consume the electrons generated from the anodic reactions (1)(2)(3)(4)(5). It is well known that during the permanganate ion reduction, (MnO 4 -gets reduced to MnO2 and adsorbs on the surface of the metal films [7][8][9]. The MnO2 can in turn be reduced to Mn2O3 and MnOOH (reactions 8,9).…”

“…It is well known that during the permanganate ion reduction, (MnO 4 -gets reduced to MnO2 and adsorbs on the surface of the metal films [7][8][9]. The MnO2 can in turn be reduced to Mn2O3 and MnOOH (reactions 8,9). However, especially, in the KMnO4 oxidizer system, similar corrosion potential values of the three films Cu, Ru and TiN indicates that the MnO2, Mn2O3 and MnOOH formed on all the three surfaces could fill the porous regions as well as form an adsorbed passive layer on the respective oxides and hydroxides.…”

“…They also found that arginine, a complexing agent, enhanced the RR of Co in the presence of H2O2 in the pH region 6-10. However, they found corrosion pits at pH 6 and 8 but not at pH 10 ( Figure. [9].…”

Corrosion inhibition of AA6063 alloy by vanadates in alkaline media

“…One area of current research in the field of corrosion inhibitors is focused on oxoanions with general formula Me n + O 4 (n-8) which are similar to chromate anion CrO 2À 4 . Molybdates, permanganates and tungstates are among the most promising inhibitors of such type [16,22,26,27]. Much attention as corrosion inhibitors for aluminum alloys was recently paid to vanadates (VO 4 3-) [10,[28][29][30][31][32].…”