SVET study of the interaction of 2-mercaptobenzothiazole corrosion inhibitor with Au, Cu and Au–Cu galvanic pair

Abstract

This study reports an electrochemical investigation of the interaction between 2-mercaptobenzothiazole (2MBT), a corrosion inhibitor, and two noble metals (Cu and Au), either isolated or under galvanical coupling. The surface reactivity of the inhibitormodified metals in chloride-containing aqueous solution of 0.1 mM NaCl was studied using the Scanning Vibrating Electrode Technique (SVET). The potential gradients in the electrolyte were detected by the SVET and converted to local ionic currents distributed at different anodic and cathodic sites, where electrochemical redox reactions are taking place. No external polarization was applied during SVET measurements, leaving the samples at the spontaneous free corrosion potential (FCP). The values of FCP showed that the metals are not protected by 2MBT. SVET revealed a moderate electrochemical activity of Au and very low in the case of Cu.