Integrated corrosion‐resistant system for AZ31B Mg alloy via plasma electrolytic oxidation (PEO) and sol‐gel processes

In this work, an integrated system that combines anodizing process with the deposition of a hybrid SiO2 sol-gel coating was developed aim improving corrosion resistance AZ31B Mg alloy. The optimization conditions using alkaline electrolyte (NaOH) modified different concentrations sodium metasilicate pentahydrate explored together preparation and sol obtained by hydrolysis condensation TEOS (tetraethoxysilane), GPTMS (3-Glycidyloxypropyl) trimethoxysilane), colloidal nanoparticles, 1-Methylimidazole (MI). surface morphology, thickness, composition were evaluated. anodized coatings thickness between 1.1 1.7 μm corresponding to magnesium oxide low silicon content. performance tested in 3.5% NaCl solution. results revealed good behavior after alloys. However, best reached when porous PEO layer sealed silica film. A decrease current density three orders magnitude is observed alloy (1.54E-06 A/cm2) multilayer (2.80E-8 A/cm2). Moreover, polarization for 8AF+SG samples showed quite high value (31546.8 Ω cm2) compared (207.3 cm2).