Corrosion behavior of carbon steel in chloride contaminated simulated concrete pore solution with carboxylate of benzoic acid and dimethylethanolamine

Abstract

Purpose

The purpose of this study is to investigate the inhibition efficiency and mechanism of a specific carboxylate corrosion inhibitor which consists of benzoic acid and dimethylethanolamine on steel surface.

Design/methodology/approach

The performance of carbon steel influenced by this organic inhibitor under different concentration of Cl⁻ and immersion time was studied by linear polarization resistance and electrochemical impedance spectroscopy in a simulated concrete pore (SCP) solution. The surface morphology and composition of steel was also analyzed by optical microscopy, SEM and EDS to investigate the effect of inhibitor on the pattern of the steel surface after long-term immersion.

Findings

Carboxylate of benzoic acid and dimethylethanolamine can increase the chloride threshold level and decrease the corrosion area of carbon steel in SCP solution with 0.6 mol/L Cl⁻ even after 120 days exposure. The inhibition mechanism of inhibitor lies in quick adsorption and buffering effect at initial time then formed deposited layer on steel surface after long-term immersion in chloride-rich environment.

Originality/value

It demonstrated that the carboxylate corrosion inhibitor not only can improve the chloride threshold level for carbon steel but also effectively decrease the corrosion rate even in chloride-rich SCP solution after long-term immersion, which is different form the conventional amino alcohol.

Citation

Liu, J.Z., Cai, J.S., Shi, L., Zhao, D., Chen, C.C., Jiang, Q. and Sha, J.F. (2017), "Corrosion behavior of carbon steel in chloride contaminated simulated concrete pore solution with carboxylate of benzoic acid and dimethylethanolamine", Anti-Corrosion Methods and Materials, Vol. 64 No. 5, pp. 555-562. https://doi.org/10.1108/ACMM-03-2016-1654