Role of V2O5 particles on the microstructures and corrosion behavior of Al–Mg–Si alloy via plasma electrolysis

Abstract

Abstract The present work investigated the effects of V2O5 on the microstructure and corrosion resistance of Al–Mg–Si alloy via plasma electrolysis (PE). For this purpose, the samples were subjected to PE in an alkaline-silicate solution under alternating current condition with a current density of 100 mA cm−2. The microstructures showed that both size and fraction of microdefects were suppressed considerably with increasing coating time. Such phenomena would be associated with the incorporation of V2O5 particles in the oxide layer whose concentration was observed to increase with increasing coating time. Thus, the electrochemical stability of the oxide layer was improved up to 3 order of magnitudes with the increase of vanadium content. The analysis of electrochemical behavior was interpreted on the basis of Tafel extrapolation and equivalent circuit model. The present method showed an extraordinary corrosion protection when compared to those of other surface treatment methods.