Electrodeposition-hydrothermal synthesis of inhibitor anion-intercalated layered double hydroxide films for corrosion resistance on steel substrates

The in-situ growth of layered double hydroxide (LDH) film on steel substrates holds huge potential for corrosion protection in reinforced concrete. However, because steel will passivate in alkaline environments, almost only CO32 -LDH films can be grown in situ on carbon steel surfaces at present, limiting the ability of LDH to release inhibitory anions. In this study, we proposed a novel electrodeposition-hydrothermal method to grow Mg/AlNO3 -LDH films in situ on Q235 steel substrates. Subsequently, CO32 , PO43 , and V2O74 anion-intercalated LDH films were successfully prepared through anion exchange to enhance their functional applications. All LDH films were dense, uniform, and exhibited good adhesion to the substrate, with a thickness of approximately 20 mu m. The electrochemical results demonstrated a significant improvement in the corrosion resistance of the steel containing LDH films. Specifically, the LDH films with intercalated inhibitory PO43 and V2O74 anions exhibited corrosion protection efficiencies exceeding 97.37 % in 3.5 wt% NaCl solution and 99.99 % in simulated concrete pore solution with chlorides.