The synergistic inhibition effect of oleic-based imidazoline and sodium benzoate on mild steel corrosion in a CO2-saturated brine solution

• Published in: Electrochimica acta Vol. 69; pp. 247 - 255
• Main Authors: Zhao, Jingmao, Chen, Guohao
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2012; Elsevier
• Subjects: Applied sciences; Carbon steels; CO2 corrosion; Corrosion; Corrosion inhibitors; Corrosion mechanisms; Corrosion prevention; Electrochemical impedance spectroscopy; Exact sciences and technology; Imidazoline; Inhibition; Inhibitor; Inhibitors; Mathematical models; Metals. Metallurgy; Sodium benzoate; Steels; Synergistic effect; Inhibitor; Sodium benzoate; Synergistic effect; Imidazoline; CO2 corrosion; corrosion; Mild steel; Aliphatic compound; Nitrogen heterocycle; Carbon dioxide; Adsorption isotherm; Monounsaturated fatty acid; X ray; Corrosion inhibition; Corrosion protection; CO; Synergism; Corrosion inhibitor; Langmuir isotherm; Saturated solution; Organic salt; Carboxylate; Photoelectron spectrometry; Gas corrosion; Electrochemical impedance spectroscopy
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2012.02.101

The corrosion inhibition of oleic-based imidazoline (OIM) and sodium benzoate (SB) on mild steel in a CO2-saturated solution was studied using a weight-loss method and a potentiodynamic polarization technique. The dependence of the impendence response on the immersion time (within 1h) in the inhibited solution was measured using electrochemical impedance spectroscopy (EIS). The results show that OIM can protect mild steel from CO2 corrosion to some extent, and its inhibition can be strengthened by using it in combination with SB. The synergistic inhibition effect of OIM and SB is obvious. The EIS measurements reveal that when the immersion time is longer than 20min, the charge transfer resistance value of the steel inhibited by OIM with SB is significantly higher than that of steel inhibited by OIM alone. The zero charge potentials of the steel in solution with and without OIM were also measured using EIS. Based on these results and an X-ray photoelectron spectroscopy analysis, an adsorption model was proposed to elucidate the synergistic mechanism between OIM and SB.