Gradient Textures Induce Micro-Galvanic Corrosion on Mg

In this study, the reason for the non-basal-plane-rich area more corrosion resistant than the basal-plane area on pure Mg in NaCl electrolyte was demonstrated based on quasi-in-situ EBSD observations. Due to the higher concentration of dissimilar crystallography orientations in the basal-plane-rich area, the gradient textures and 'micro-texture' galvanic couples were promoted. This exacerbates the progression of localized corrosion in basal-plane-rich area, ultimately deteriorating the overall corrosion performance of Mg. Randomizing the gradient texture diminishes the tendency towards micro-galvanic corrosion and enhances the corrosion resistance of Mg. These findings shed light on yet another facet of complex mechanism of Mg corrosion.