LDH-inhibitor conversion film on steel rebar for mitigating chloride-induced corrosion in reinforced concrete environment

To enhance the targeted and long-term corrosion protection of steel reinforcement against chloride-induced corrosion, a layered double hydroxide (LDH) conversion film is grown on the steel surface with corrosion inhibitor ions loaded into the LDH film. The results demonstrate that the proposed method successfully synthesize a corrosion-resistant film (∼ 1 μm thick) on the steel substrate. The film, primarily composed of Mg, Fe, Cr, O, C, N, and Ca elements, exhibited a uniform surface coverage of petal-like LDH-Inhibitor nanosheets. Among the preparation parameters, a hydrothermal reaction time of 36 h yielded the film with the best corrosion resistance. In simulated concrete pore solution, the LDH-Inh-36 h film increased the critical chloride concentration for corrosion initiation from 0.17 to 0.27 mol/L. These findings indicate that the LDH-Inhibitor film provides effective protection for steel rebar against chloride-induced corrosion, representing a promising strategy for enhancing reinforced concrete durability in marine environments.