Thermodynamic properties of<i>Thymus satureioides</i>essential oils as corrosion inhibitor of tinplate in 0.5 M HCl: chemical characterization and electrochemical study

Abstract

Abstract Thymus satureioides (TS) oil was hydrodistillated and analyzed by chromatography. The natural oil was tested as a green inhibitor for tinplate in 0.5 M HCl solution. Electrochemical parameters of different concentrations of TS oil and the corresponding corrosion inhibition efficiencies were reported. Polarization data indicated that the studied oil acts as a mixed type inhibitor without changing the mechanism of hydrogen evolution reaction. The effect of temperature (25–60°C) on the inhibition efficiency at different concentrations of the oil studied was investigated. The data revealed that the TS oil might exhibit good inhibition even at moderate to high temperatures. The corrosion activation parameters (Ea, ΔH*, ΔS*, and ΔG*) were estimated and discussed. It was found that the Ea values for tinplate corrosion in the inhibited solutions were higher than that for the uninhibited solution, indicating good inhibitor characteristics with a physical adsorption mechanism.