Investigation of Cr and rare earth (RE) on the corrosion resistance of HRB400 rebar in simulated concrete pore solutions containing chloride and sulfate ions

The effect of Cr and rare earth (RE) on the corrosion resistance of HRB400 in simulate concrete pore solution containing Cl- and SO42- was investigated. The results of electrochemical tests and corrosion morphology observations revealed that HRB400 corrosion rates increased with sulfate concentration, but Cr/RE addition notably reduced rates and passive current density, particularly in high sulfate conditions, suggesting a sulfate-Cr/ RE interaction. The mechanism involves structural changes in the surface passivation film. Furthermore, the combination of Cr and RE effectively mitigated localized corrosion risk compared to Cr alone, highlighting their synergistic corrosion resistance enhancement.