Corrosion Inhibition Effect of Thiol-phosphonic Acid Mixed Self-assembled Monolayers on 2024 Aluminum Alloy

1-tetradecanethiol (TDT), 1-tetradecylphosphonic acid (TDPA) and TDT-TDPA mixed solutions were prepared using mixtures of absolute ethanol and water with different volume ratios as the solvents, then self-assembled monolayers (SAMs) of TDT, TDPA and mixed TDT-TDPA were deposited on the surfaces of 2024 aluminum alloy by immersing method in the solution. The adsorption behavior and corrosion inhibition performance of SAMs were investigated by potentiodynamic scanning, EIS, contact angle test and XPS. The results indicated that all three kinds of SAMs showed a certain inhibition effect on the aluminum alloy in Harrison solution, and the inhibition efficiency increased with the increase of water content in the assembly solution. The mixed SAM showed more prominent corrosion inhibition performance compared to the single SAMs.