Corrosion inhibition of copper and aluminium by 2-mercaptobenzimidazole and octylphosphonic acid—Surface pre-treatment and method of film preparation. (1st November 2022)

• Record Type: Journal Article
• Authors: Kozlica, Dževad K.; Milošev, Ingrid
• Is Part Of: Electrochimica acta. Volume 431(2022)
• Publication Date: 2022-11-01
• Subjects: Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2022.141154
• Languages: English
• ISSNs: 0013-4686

Abstract

Highlights: 2-mercaptobenzimidazole is an efficient inhibitor for Cu but not for Al; with octyphosphonic acid is vice versa. Mechanical and chemical substrate pre-treatments are not the most determining factor for inhibition. Method of preparation is crucial for the degree of protection. Inhibition is successful only for films prepared in an aqueous NaCl solution. Inhibition is not successful for films prepared in an ethanol solution. Abstract: The optimal surface pre-treatment conditions for improved adsorption of 2-mercaptobenzimidazole (MBI) and octylphosphonic acid (OPA) on copper and aluminium substrates are presented. For this purpose, mechanical and chemical pre-treatments were employed, which included grinding/polishing and etching/desmutting, respectively. In addition, organic films for both pre-treated samples were prepared by liquid-phase deposition from ethanol or an aqueous solution containing MBI and OPA inhibitors. The mechanism of formation and degradation of the films on Cu and Al samples in 3 wt.% NaCl were investigated by electrochemical methods, whereas morphology and bonding of inhibitors were studied by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. It was shown that the surface pre-treatment did not significantly influence the chemistries of Cu and Al. However, the method of film formation, including the use of two different solvents, was crucial. The inhibitor films on Cu and Al were not formed in an ethanol solution but only deposited from aqueous solutions. A significant reduction in corrosion current density revealed that MBI is an effective inhibitor for Cu, while this characteristic is absent for Al. On the other hand, OPA behaves the other way around. Graphical abstract: Image, graphical abstract