Corrosion inhibition performance of RNC-n on aluminum alloy surface in alkaline solution

Abstract

The corrosion inhibition behavior of glycine surfactants with different carbon chain lengths (RNC-n, n = 8, 12, 14) of AA2024-T3 aluminum alloy in 0.01 mol·L−1 NaOH solution was investigated. The weight loss and electrochemical methods, XPS, SEM/EDS techniques, quantum chemical calculations, and molecular dynamics simulations were used for studying the corrosion inhibition properties, adsorption behavior, and corrosion inhibition mechanism. When the maximum solubility of 0.01 mol·L−1 was achieved, the inhibition effectiveness of RNC-8 reached 90.55 %. Both RNC-12 and RNC-14 exhibited inhibitory efficiencies of 92.81 % at 0.005 mol·L−1 and 91.83 % at 0.0005 mol·L−1. RNC-n was shown to be an anodic corrosion inhibitor, since its impact on the anodic reaction was larger than on the cathodic one. RNC-n was able to successfully adsorb on the aluminum surface and form a protective film, which hindered further corrosion damage of the aluminum by the alkaline solution. In addition, the adsorption sites of RNC-n molecules were analyzed, and it was found that the adsorption sites of the corrosion inhibitor were mainly in the carboxyl group. Therefore, this paper can provide some theoretical support for the protection of aluminum alloys against corrosion in alkaline medium.