| LIU Qian,LIU Jin-yan,WANG Jia,CHONG Yao.Synergistic Inhibition Effect of 2-Mercaptobenzimidazole and L-cysteine on Q235 Steel in HCl[J],51(10):250-259, 208 |
| Synergistic Inhibition Effect of 2-Mercaptobenzimidazole and L-cysteine on Q235 Steel in HCl |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.10.026 |
| KeyWord:corrosion inhibitor synergistic inhibition effect Q235 steel 2-mercaptobenzimidazole L-cysteine electrochemistry |
| Author | Institution |
| LIU Qian |
School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Inner Mongolia Baotou , China |
| LIU Jin-yan |
School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Inner Mongolia Baotou , China |
| WANG Jia |
School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Inner Mongolia Baotou , China |
| CHONG Yao |
School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Inner Mongolia Baotou , China |
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| Abstract: |
| Adding corrosion inhibitor is the most effective measure to protect metal surface from corrosion in acidic environment, which has the advantages of low cost, simple operation and high efficiency. This paper studies the corrosion inhibition performance of 2-mercaptobenzimidazole (MBI), L-cysteine and their mixtures on Q235 steel in 1 mol/L HCl solution, the optimal mixing conditions between MBI and L-cysteine is investigated by static weight loss method, electrochemical impedance spectroscopy and polarization curve. The corrosion inhibition mechanism of MBI and L-cysteine on the surface of carbon steel is further analyzed by atomic force microscope (AFM) and X-ray photoelectron spectrometer (XPS).The Q235 carbon steel samples that cut by a molybdenum wire cutter into 20 mm×30 mm×3 mm and 10 mm×10 mm× 3 mm are polished by 120#、240#、400#、600#、800# metallographic sandpaper, then by 1 200# to a mirror-smooth surface under running water. After that, rinse the metal sample with distilled water, anhydrous ethanol, acetone and dry it with cold wind. In the static weight loss experiment, soak the samples (20 mm×30 mm×3 mm) in HCl solutions without and with corrosion inhibitors for 24 hours at temperature of 30 ℃. After that, the removed samples are scrubbed, dry and weigh. The experimental data obtained by this method are used to calculate the inhibition efficiency. The results show when MBI is used alone at a concentration of 5×10‒3 mol/L, the corrosion inhibition efficiency reaches 88.21%, while at the same concentration, the corrosion inhibition efficiency of L-cysteine is only 60.12%. It is worth noting that when L-cysteine is added to HCl solution containing MBI, the inhibition efficiency will increase significantly, especially when the concentration is 1×10‒3 mol/L and the compound ratio is 9∶1, the corrosion inhibition efficiency reaches the best (95.84%), i.e the corrosion inhibition efficiency of MBI-L-cysteine at a concentration which is lower than the optimal concentration of MBI or L-cysteine used alone, is higher than their respective best corrosion inhibition efficiency. In addition, the synergy effect between MBI and L-cysteine is the most obvious.The electrochemical tests including electrochemical impedance method and potentiodynamic polarization curve method are carried out on the electrochemical work station. The results are consistent with weightlessness method, and further indicates that the mixture of 2-mercaptobenzimidazole and L-cysteine simultaneously are mixed type corrosion inhibitor that predominant cathodic control over the reaction. AFM topography and XPS spectrum respectively show the surface of Q235 immersed in solution containing MBI-L-cysteine (concentration are 1×10‒3 mol/L, compound ratio is 9∶1) is relatively smoother, and the protective film formed by them on Q235 steel through adsorption can significantly enhance the acid resistance of Q235 steel. |
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