Superhydrophobic Corrosion Inhibitor Intercalated Hydrotalcite Coating for Enhanced Corrosion Resistance of the Aluminum

Based on the ion exchange properties of hydrotalcite, dense hydrotalcite films with citric acid or tetraborate ions were prepared by a one-step hydrothermal method on aluminum flake, and superhydrophobic modified by sodium laurate to obtain a superhydrophobic corrosion resistant film with a water contact angle of about 154° and a sliding angle of less than 5°. The super hydrophobicity of the film can greatly slow down the infiltration of water and corrosive ions. The LDHs can release corrosion inhibitor ions to promote the formation of the passivation layer and can absorb chloride ions to reduce the corrosion of the metal. In addition, a very uniformly grown hydrotalcite film was obtained using urea. Electrochemical analysis of the coating after immersion in 3.5 wt % NaCl solution has shown that U-LDH-SC/SL film has the most positive corrosion potential (−0.056 eV), the best corrosion resistance, and long-term stability, which is related to the larger layer spacing and more uniform growth.