Influence of Vanadate Additive on the Properties of Cerium Conversion Coatings on AZ91 Magnesium Alloys

Abstract

The present study investigates the microstructure and corrosion resistance of the cerium conversion coating on AZ91 magnesium plates in the cerium nitrate/hydrogen peroxide aqueous solution with and without sodium metavanadate. The microstructure characterization shows that the conversion coating displays a twolayered structure, an inner porous layer and an outer compact layer. Moreover, the size and population density of blisters are significantly reduced with the addition of NaVO 3 to the solution. The corrosion resistance is improved due to the decrease in defects within the coating.