First-principles analysis of effects of cerium doping on electrochemical corrosion behaviors of steel

Abstract

Based on first-principles calculation framework, the surface model, anodic dissolution , cathodic oxygen absorption reaction, and other related electrochemical corrosion models of Fe-Ce system were constructed, and the influencing mechanism Ce doping on the corrosion resistance of Fe-Ce system in the Cl medium environment was analyzed. The results show that Ce doping on the first surface and subsurface inhibits the ionization of Fe atoms and greatly promotes the repassivation process of Fe matrix. Ce doping on the first layer is conducive to preventing the detachment of surface Fe atoms from Fe matrix and delaying the occurrence of corrosion. Ce atoms in the subsurface effectively increase the difficulty of Fe atoms detaching from the matrix at high Cl concentrations. When O diffusion is the controlling link of oxygen absorption reaction, Ce doping has no effects on the reaction rate of cathodic oxygen absorption. Ce doping enhances the electrochemical stability of Fe(100) 1 and reduces the anodic dissolution rate of Fe matrix, thereby improving its corrosion resistance . The doping of Ce enhances the interlayer binding energy and adhesion between the monolayer O atom and Fe matrix. Furthermore, Ce atoms increase the difficulty of Fe atoms detaching from the matrix at high Cl concentrations. Moreover, Ce doping on the first surface of Fe can reduce the anodic dissolution rate of the system, thus delaying the occurrence of corrosion.