The Influence of Surface Preparation on Corrosion-Protection Properties of Oxide Layers Formed on MA8 Magnesium Alloy by Microarc Oxidation

Abstract—A MA8 magnesium alloy substrate was pre-impregnated in aqueous solutions of cerium(III) nitrate and glycerol before microarc oxidation, which was used to form oxide ceramic coatings from a silicate–alkaline electrolyte containing fluoride ions. The corrosion-protection properties of these coatings on the pre-impregnated alloy surface were assessed using potentiodynamic polarization curves. Electrochemical parameters calculated from the potentiodynamic polarization curves showed that the presence of the oxide ceramic coating on the surface of MA8 magnesium alloy significantly reduces the corrosion current density and increases the polarization resistance. It was determined that the pre-impregnation of the MA8 magnesium alloy substrate in aqueous solutions of cerium(III) nitrate and glycerol affects the mechanism of the corrosion damage.