Anti-corrosion mechanism of MgAl-LDHs inhibitors with varying anionic charge on reinforcing steel in simulated concrete pore solutions

Abstract

The effect of anionic charge of MgAl-LDHs on the corrosion behaviors of reinforcing steel induced by chloride was carefully explored in this study through electrochemical methods and DFT simulations. The results show that the binding energies (EB) was more negative as anionic charge increased. Therefore, the chloride exchange rate (δ) of LDHs-PO43− was much smaller than that of LDHs-H2PO4− and LDHs-PO3F2−, leading to the worst anti-corrosion efficiency of LDHs-PO43−. Moreover, CaF2 could be formed in the LDHs-PO3F2− specimen, which improved the compactness of protective layer on the steel surface, resulting in that LDHs-PO3F2− had a higher anti-corrosion efficiency than LDHs-H2PO4−.