| Abstract Scope |
The anti-corrosion performance of passive oxides, such as Al2O3, highly depends on the thermodynamics and kinetics of point defects in the bulk and on surfaces of these oxides under electrochemical conditions. Here I would like to present two examples of ab-initio studies of these point defects. First, we combined empirical interatomic potential and density functional theory (DFT) calculations to search the accurate structures and energetics of point defects in bulk α-Al2O3. It suggests that, at the electrochemical conditions where liquid water is thermodynamically stable, the point defect formation reactions in the crystalline α-Al2O3 can be exothermic. It naturally explains the amorphous structures of alumina at the Al/water interfaces. Second, we studied the stability of point defects at the interface between alumina and electrolyte that contains chlorine under different local chemical and structural conditions, which can be helpful for the design of passive oxide layers with high resistance to localized corrosions. |