Corrosion inhibition effect of betaine type quaternary ammonium salt on AA2024-T3 in 0.01 mol·L−1 NaOH: Experimental and theoretical research

Abstract

The corrosion inhibition performances of Betaine type quaternary ammonium salt: 2-(DodecyldiMethylaMMonio) acetate (BS-12), Betaine hydrazide hydrochloride∼(Carboxymethyl) trimethylammonium chloride hydrazide (GRT) on AA2024-T3 in 0.01 mol·L−1 NaOH solution were studied by means of the weight loss method (WLM), electrochemical impedance spectroscopy (EIS), potential polarization curve. It was found that the tested molecules were effective inhibitors and their inhibition efficiency was remarkably increased (BS-12: 68.75% ∼ 92.61%, GRT: 70.12% ∼ 98.94%) with a rising concentration (1 × 10−3 ∼ 1 × 10−1 mol·L−1), and the ability resisting corrosion of GRT was the most outstanding. Moreover, used inhibitors represent mixed-type inhibitors that inhibit the anodic reaction significantly. The surface analysis results (atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and electronic energy spectrum analyzer (EDS)) illustrated that the presence of protective film formed by corrosion inhibitors on AA2024-T3. Quantum chemical calculations and molecular dynamics simulation manifested that the chemisorption between the corrosion inhibitor molecule and the metal was achieved through the electronic transfer. Moreover, GRT possessing a smaller energy gap (ΔE, 3.434 eV), the fraction of electron transfer (ΔN, 0.0992) and a more negative energy of adsorption (Eadsorption, -195.017 kcal/mol) could better protect the integrity of the metal relative to BS-12. The theoretical research was in good agreement with the experimental results.