Kinetics and mechanism of corrosion of oxide coating fabricated on aluminum alloy by the plasma electrolytic oxidation in molten salt. (November 2022)

• Record Type: Journal Article
• Authors: Sobolev, Alexander; Bograchev, Daniil; Borodianskiy, Konstantin; Zinigrad, Michael
• Is Part Of: Corrosion science. Volume 208(2022)
• Publication Date: 2022-11
• Subjects: A. Aluminum -- B. Electrochemical calculation -- B. Polarization -- B. EIS -- C. Kinetic parameters -- C. Oxide coatings; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110604
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: The kinetics and mechanism for the degradation of oxide coatings obtained by the Plasma Electrolytic Oxidation method in molten salts on AA1050 aluminum alloy were studied. The effect of the corrosive medium on the morphology and phase composition of the samples was investigated. The influence of the concentration of oxygen and chloride ions on the corrosion rate was studied. It is demonstrated that the polarization resistance of samples with oxide coatings is three orders of magnitude greater than that of the untreated alloy. The main features of the corrosion process are considered, and a corrosion mechanism is proposed. Highlights: An anticorrosion coating (Al2 O3 ) was developed on an Al 1050 alloy by plasma electrolytic oxidation in a molten salt. The corrosion proceeds without diffusion limitations in the mode of delayed discharge with the transfer of one electron. Corrosion currents and potentials and transfer coefficients are determined. The anodic process decreases with electrolyte stirring. Increasing the oxygen concentration increases the cathodic reaction. The effect of chloride-ion concentration on the corrosion rate was studied. A corrosion mechanism is proposed.