Assessment of dimethylbenzodiimidazole as corrosion inhibitor of austenitic stainless steel grade 316L in acid medium Article uri icon

abstract

  • In this research the performance of an imidazole derivative [Dimethylbenzodiimidazole (2,7-dimethyl-3,6-dihydrobenzo[1,2-d;3,4-d%27] diimidazole)] (BDI) as organic inhibitor to minimize pitting corrosion of 316L Stainless Steel in sulphuric acid solution at room temperature was evaluated by means of electrochemical measurements. The inhibitor concentrations studied in the system steel/acid were 0, 10, 20, 40, 60, 80, 100 and 120 ppm. Electrochemical techniques as polarization curves and electrochemical impedance spectroscopy (EIS) were employed to evaluate the inhibitor behavior. The results of polarization curves showed that BDI causes a shift at the corrosion potential to more positive values, and a decrease in the corrosion current, indicating that the inhibitor restricts the anodic metal dissolution reaction, so, the inhibitor was classified into anodic type. Whereas, the impedance spectra (e.g. Nyquist plots) showed a continuous increase of the diameter of semicircle, which is associated to the charge transfer resistance (Rct) as a function of increasing inhibitor concentration, this behavior follows the mechanism of physical adsorption of the molecule leading to the formation of a protective barrier layer on steel surface. Also, it was found that the greatest corrosion inhibiting efficiency (IE) was attained at 40 ppm. This is sufficient reason to consider that the organic compound BDI is a good alternative as corrosion inhibitor for 316L Stainless Steel in acid medium. © 2015 The Authors.
  • In this research the performance of an imidazole derivative [Dimethylbenzodiimidazole (2,7-dimethyl-3,6-dihydrobenzo[1,2-d;3,4-d'] diimidazole)] (BDI) as organic inhibitor to minimize pitting corrosion of 316L Stainless Steel in sulphuric acid solution at room temperature was evaluated by means of electrochemical measurements. The inhibitor concentrations studied in the system steel/acid were 0, 10, 20, 40, 60, 80, 100 and 120 ppm. Electrochemical techniques as polarization curves and electrochemical impedance spectroscopy (EIS) were employed to evaluate the inhibitor behavior. The results of polarization curves showed that BDI causes a shift at the corrosion potential to more positive values, and a decrease in the corrosion current, indicating that the inhibitor restricts the anodic metal dissolution reaction, so, the inhibitor was classified into anodic type. Whereas, the impedance spectra (e.g. Nyquist plots) showed a continuous increase of the diameter of semicircle, which is associated to the charge transfer resistance (Rct) as a function of increasing inhibitor concentration, this behavior follows the mechanism of physical adsorption of the molecule leading to the formation of a protective barrier layer on steel surface. Also, it was found that the greatest corrosion inhibiting efficiency (IE) was attained at 40 ppm. This is sufficient reason to consider that the organic compound BDI is a good alternative as corrosion inhibitor for 316L Stainless Steel in acid medium. © 2015 The Authors.

publication date

  • 2015-01-01