Analysis of the surface film formed on Mg by exposure to water using a FIB cross-section and STEM-EDS

► Examined surface film formed on Mg sample in pure water using STEM-EDS. ► FIB milling allows preparation of a debris-free thin film cross-section sample. ► Direct imaging confirms diffuse MgO/Mg(OH)2 surface film forms. ► Chemical breakdown (hydration) of native MgO layer is a precursor step to corrosion.