Correlative study of Mott–Schottky analysis and corrosion behaviour of plasma electrolytic oxidation treated magnesium alloy: Effect of Cl⎺ concentrations

Abstract

Semiconducting and corrosion properties of the plasma electrolytic oxidation treated AM50 magnesium alloy was correlatively investigated as a function of Cl⎺ content. Semiconducting character transitioned from p – type (for 0.01 M Cl⎺) to n – type (for both 0.1 and 1 M Cl⎺). Corrosion potential moved progressively to noble potential with the increase in Cl⎺ content. Variations of impedance modulus at lowest frequency employed (|Z| resistance of inner barrier layer (R IL 0.1 Hz ), ), and corrosion current density with the Cl⎺ content were correlated with the variations of the defect density, change in E corr – E fb . and thickness of space charge layer.