Synergism of imidazoline and sodium dodecylbenzenesulphonate inhibitors on corrosion inhibition of X52 carbon steel in CO2-saturated updates chloride solutions

In this work, the inhibition performance of imidazoline (IM) and sodium dodecylbenzenesulphonate (SDBS) inhibitors on corrosion of an X52 carbon steel in CO2-saturated chloride solutions at 60 degrees C was investigated by surface characterization, weight-loss testing and electrochemical measurements. A synergism of the two inhibitors exists to enhance the corrosion inhibition performance compared to the inhibitors acting independently. The synergism is attributed to the co-adsorption of elements sulfur from SDBS and nitrogen from IM on the exposed iron atoms, forming a more compact, more uniform and denser film on the steel surface than the films formed in the presence of either IM or SDBS where the repulsive force exists among the adsorbed inhibitor molecules. The adsorption of both inhibitors on the steel is chemisorption, following the Temkin adsorption isotherm. (C) 2019 Elsevier B.V. All rights reserved.