Passivation and depassivation properties of Cr-Mo alloyed corrosion-resistant steel in simulated concrete pore solution

This paper is aimed to investigate the passivation and depassivation properties of the Cr-Mo corrosion resistance (CR) steel in the simulated concrete pore solution (SCPS). Electrochemical methods, XPS and AFM tests were used to investigate the composition and morphology characterizations of passive film. As the results shown, passivation of CR steel will start and complete in the SCPS in one or two days, while that of LC steel is in three days. The passive film is mainly composed of metal oxides or hydroxides, and the metal oxidation degree varies with depth of the film. When exposed to Cl- with a concentration high enough, the passive film will be gradually dissolved. The CR steel shows higher corrosion resistance than the LC steel. By theoretical analysis, the growth of passive film can be divided into four steps. The theoretical thickness of the CR steel is thinner than that of the LC steel.

Automated summary

This study investigated the passivation and depassivation properties of Cr-Mo corrosion resistance steel in simulated concrete pore solution. The results showed that CR steel exhibited higher corrosion resistance compared to LC steel. The passive film mainly consisted of metal oxides or hydroxides, and the passivation process could be divided into four steps.