Corrosion behaviour of API 5LX52 steel in HCl and H2SO4 media in the presence of 1,3-dibencilimidazolio acetate and 1,3-dibencilimidazolio dodecanoate ionic liquids as inhibitors

• 1,3-dibencilimidazolio acetate (DBImA) and 1,3-dibencilimidazolio dodecanoate (DBImL) are a good inhibitors in HCl medium.
• Inhibitor with long alkyl chain are better for corrosion protection.
• Corrosion resistance increase with the ionic liquid concentration.
• Adsorption of the inhibitor obeys a Langmuir isotherm.

Two ionic liquids, 1,3-dibencilimidazolio acetate (DBImA) and 1,3-dibencilimidazolio dodecanoate (DBImL), were investigated as corrosion inhibitors in 1.0 M HCl and H2SO4 solutions. The data extracted from Tafel plots, electrochemical impedance spectroscopy and SEM indicate a high inhibition effectiveness in HCl solution. A dense layer of physisorbed inhibitor prevents the diffusion of ionic species from the film and/or the attack of the surface by ions in solution. The protection efficiency increases as the concentration of the inhibitors increases. The adsorption of these inhibitors on steel surfaces obeys the Langmuir isotherm.