Preparation of MgAl layered double hydroxides intercalated with nitrite ions and corrosion protection of steel bars in simulated carbonated concrete pore solution

Mg-Al layered double hydroxides intercalated with nitrite ions was prepared by three different methods: calcined-rehydration (R-LDH), hydrothermal (H-LDH) and coprecipitation (C-LDH) method. The products were characterized and the results indicated that C-LDH had the highest intercalated rate of anions. The ion substitution test also verified C-LDH exhibited the largest adsorption capacity of chloridion. The inhibition efficiency and corrosion current density of C-LDH from electrochemical test both had the better performance than R-LDH and H-LDH over immersion time. Therefore, C-LDH could had the best anticorrosion in a long period and its mechanism of corrosion protection was also discussed.