Corrosion inhibition of AA2024-T3 in alkaline solution by disodium-N-dodecyliminodiacetate: Experimental and theoretical studies

Abstract

To enhance the corrosion resistance of AA2024-T3 in 0.01 mol·L−1 NaOH aqueous solution, the inhibition characteristics of the amphoteric surfactant disodium-N-dodecyliminodiacetate (RNC-12) were assessed by means of the static weight loss method, electrochemical impedance spectroscopy, potentiodynamic polarisation curves, atomic force microscopy and X-ray photoelectron spectroscopy, and the results were compared with those of sodium laurate (SL). Quantum chemical calculations and molecular dynamics (MD) simulations were also performed to predict and analyse the relationships between the molecular structure and inhibition efficiency. The results of the experiments revealed that RNC-12 achieved a higher inhibition efficiency of 91% as a valid inhibitor of AA2024-T3 in alkaline medium compared with SL (81%). The results of surface analysis showed that the two inhibitors could be well adsorbed on the alloy surface, and the degree of surface corrosion was as follows: without inhibitor >SL >RNC-12. Quantum chemical calculations and MD simulations showed that the anionic state of RNC-12 possesses a smaller band gap, larger dipole moment, and more negative energy of adsorption, indicating that RNC-12 is more easily adsorbed on the alloy surface than SL. Therefore, the experimental results were in accordance with the theoretical calculations.