(544dt) Effect of Water, pH and Electrochemical Potential on Cl Adsorption on Cr2O3 Passive Film

Stainless steel are important materials for nuclear industry applications and are extensively used in light water reactors (LWR). The corrosion resistance of stainless steel is attributed to the presence of chromium that segregates to the surface to form Cr₂O_3, a strong passive layer that provides corrosion protection for the material. However, this passive film is susceptible to breakdown in acidic, chlorinated solutions often present in LWRs. Chlorine is one of the prominent elements in LWR water chemistry and has been observed to facilitate the breakdown of metal oxides like Fe₂O₃. This study uses first principles via density functional theory to examine the impact of water, pH and electrochemical potential on adsorption of chlorine on the α-Cr₂O₃ (0001) surface and the initial breakdown steps of the passive film. The determination of the chlorine adsorption behavior is essential to understand and predict the stability of the chlorine on and in the passive film and the effect on corrosion resistance.