Stabilization of AZ31 Mg alloy in sea water via dual incorporation of MgO and WO3 during micro-arc oxidation

This study investigated the surface characteristics of WO3-MgO oxide layers formed on AZ31 Mg alloy via micro-arc oxidation (MAO). A series of MAO coatings was performed in an alkaline-aluminate electrolyte containing two different concentrations (2 and 4 g/L) of WO3 nanoparticles, and the results were compared to those without WO3 particles. Microstructural observations revealed that the addition of 2 g/L of WO3 nanoparticles into the electrolyte led to a uniform distribution of nanoparticles throughout the thickness of the oxide layer. In contrast, WO3 nanoparticles tended to agglomerate on the surface upon the inclusion of 4 g/L of WO3 into the electrolyte. The filling of structural defects due to the uniform incorporation of WO3 in the case of 2 g/LWO3 would be responsible for the superior corrosion resistance of the MAO-treated AZ31 Mg alloy substrate. (c) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the surface characteristics of WO3-MgO oxide layers formed on AZ31 Mg alloy via micro-arc oxidation (MAO) with different concentrations of WO3 nanoparticles. The addition of 2 g/L of WO3 nanoparticles led to a uniform distribution throughout the thickness of the oxide layer and improved corrosion resistance.