Synthesis of a dibenzimidazole compound and its corrosion inhibition behavior on AZ91D Mg alloy in 3.5 wt.% NaCl solution

• Published in: Journal of molecular structure 2023-11, Vol.1291, p.136065, Article 136065
• Main Authors: Xu, Xingxin, Qu, June, Huang, Hualiang
• Format: Article
• Language: English
• Subjects: Corrosion inhibitors; Electrochemical measurements; Mg alloy; Synthesis; Theoretical calculations
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2023.136065

•An efficient magnesium alloy corrosion inhibitor (BBI) was synthesized.•The corrosion inhibition behavior of BBI on AZ91D magnesium alloy was studied.•The adsorption behavior and corrosion inhibition mechanism of BBI were discussed. In this work, a low-cost and easily purified small molecule dibenzimidazole compound (BBI) was synthesized by the condensation of o-phenylenediamine and malonic acid. BBI was a new corrosion inhibitor for magnesium alloys and its corrosion inhibition behavior on AZ91D magnesium alloy was studied by electrochemical measurements, surface analysis and theoretical calculations in 3.5 wt.% NaCl solution at 30 °C. The adsorption behavior and corrosion inhibition mechanism of BBI molecules were discussed. It was found that BBI exhibited excellent inhibition effect on the corrosion of magnesium alloy. When BBI concentration was 0.25 g/L, the optimal corrosion inhibition efficiency was 86.2%. The adsorption of BBI molecule obeyed Langmuir adsorption on the surface of magnesium alloy, and one side of BBI molecule was adsorbed on the surface of magnesium alloy in parallel through physical and chemical mixed adsorption. The synthetic route, electrostatic potential diagram and equilibrium adsorption configuration of BBI. [Display omitted]