2-Mercaptobenzimidazole as a copper corrosion inhibitor: Part I. Long-term immersion, 3D-profilometry, and electrochemistry

• 2-Mercaptobenzimidazole is a very effective Cu corrosion inhibitor in 3 wt.% NaCl.
• Corrosion of inhibited Cu follows kinetic-controlled and diffusion-controlled processes.
• 2-Mercaptobenzimidazole is a mixed-type corrosion inhibitor.

The high corrosion inhibition effectiveness of 2-mercaptobenzimidazole (MBIH) in 3 wt.% aqueous NaCl solution is reported using long term immersion tests, 3D-profilometry, electrochemical impedance spectroscopy, and potentiodynamic curve measurements. The high corrosion inhibition performance was proven after 180 days of immersion. The impedance spectra were characterized by two time constants relating to charge transfer and finite layer thickness or semi-infinite diffusion of copper ions through the surface layer, therefore Cu corrosion in solution containing MBIH follows kinetic-controlled and diffusion-controlled processes. Moreover, it is shown that MBIH is a mixed-type inhibitor.