Research on the Mechanism of the Influence of Chromium and Nitrogen Elements on the Formation of the Passivation Film on the Surface of High-Nitrogen Steel

Abstract

The excellent corrosion resistance of high-nitrogen steel is related to the passivation film on its surface. However, the mechanism by which nitrogen and chromium atoms affect the formation of the passivation film remains unclear. Electrochemical test results show that nitrogen and chromium promote the formation of the passivation film and secondary passivation. The calculation results indicate that oxygen atoms tend to adsorb on the Fe(111) surface, and chromium doping enhances the adsorption of oxygen atoms. Nitrogen doping increased the segregation energy of chromium toward the surface by 79.8%, promoting the segregation of chromium toward the surface, which further enhanced the adsorption of oxygen atoms on the Fe(111) surface. The synergistic effect of nitrogen and chromium causes oxygen atoms to rapidly accumulate on the Fe(111) surface, forming a protective passivation film, which is the fundamental source of corrosion resistance. In addition, the d-band center is positively correlated with oxygen adsorption energy, indicating that increasing the d-band center on the surface can enhance the adsorption of oxygen atoms, promote the formation of passivation films, and improve corrosion resistance. These findings provide theoretical insights and strategies for studying and controlling the corrosion resistance of materials.