Study of the inhibition mechanism of imidazolines by electrochemical impedance spectroscopy

In this paper, the results of evaluating the activity of imidazoline-based corrosion inhibitors by means of electrochemical impedance spectroscopy (EIS) and other traditional electrochemical methods are reported. Tests were carried out on AISI 1040 (UNS G10400) mild steel specimens immersed in solution simulating the composition of an aqueous phase during oil production and transportation: high salinity, presence of carbon dioxide (CO2), anaerobic environment, 40 degrees C temperature. Two different inhibitor formulations were tested in the presence of different salting agents (acetic acid [CH3COOH] and thioglycolic acid [HSCH2COOH or TGA]). EIS data were analyzed using equivalent circuits. The electrochemical tests indicated evidence of different mechanisms and activity depending on inhibitor formulation