The influence of Cr and Mo on the formation of the passivation film on the surface of ferritic stainless steel

The excellent corrosion resistance of ferritic stainless steel is closely related to the formation rate and stability of the passivation film. The mechanism of alloy atoms in the formation of the passivation film is not yet clear. Based on density functional theory, the influence of chromium and molybdenum elements on the adsorption of oxygen atoms was studied. The results show that oxygen atoms tend to adsorb on the Fe(110) surface, and doping with chromium and molybdenum can promote the adsorption of oxygen atoms on the surface. The bond population and charge population between oxygen atoms and surface atoms also significantly increase, attributed to the enhancement of the surface d-band center by chromium and molybdenum doping. Additionally, there is a clear positive correlation between the d-band center and the adsorption energy of oxygen atoms, suggesting that corrosion resistance can be regulated by changing the d-band center of the surface. The computational results reveal the fundamental reasons for the improvement of corrosion resistance in ferritic stainless steel by chromium and molybdenum elements, providing theoretical guidance and effective means for the study and control of material corrosion resistance.