Thymus algeriensis extract as a new eco-friendly corrosion inhibitor for 2024 aluminium alloy in 1 M HCl medium

Abstract The inhibitive behaviour on 2024 aluminium alloy of Thymus algeriensis extract was investigated in an aerated 1 M HCl solution via weight loss, gasometric and electrochemical impedance spectroscopy (EIS) techniques. It was found that the addition of the extract reduces the corrosion rate of aluminium alloy. The inhibition efficiency increases with increasing extract concentration and attained 78.7% at 0.75 g/L. The inhibitive effect of the tested extract was discussed in view of adsorption of its components on the aluminium surface. The adsorption of the extract components of T. algeriensis on the aluminium alloy surface follows Langmuir adsorption isotherm. The effect of the temperature on the corrosion behaviour with addition of the optimal concentration of T. algeriensis extract was studied in the temperature range of 298 and 338 K. The inhibition efficiency is independent of temperature. The presence of extract increases the activation energy of the corrosion process of aluminium alloy. The synergistic action caused by iodide ions on the corrosion inhibition of aluminium in 1 M HCl by 0.75 g/L was studied using weight methods at 298 K. The inhibition efficiency synergistically increased on addition of potassium iodide.