Effect of ytterbium oxide on the structure and corrosion resistance of micro-arc oxide coatings of Mg-Nd binary alloys in the natural seawater

MAO coatings were prepared on Mg-0.5Nd by adding four different concentrations of Yb2O3 in the electrolyte. The thickness, microstructure and chemical composition of the MAO coating were characterized. The results revealed that the thickness of MAO coating after adding Yb2O3 reduced 1/2 to the original. But the compactness of MAO coating was improved after adding Yb2O3. The compactness and corrosion resistance of MAO coating were positively correlated with Yb2O3 concentration.