Investigation of Thermodynamic Behavior and Inhibition Effect of Thiazole Nitramide Compound on Corrosion of Steel Pipeline X70 in Acidic Solution

In this research, the corrosion inhibition of X70 steel in HCl containing 2-amino-5-nitrothiazole as an inhibitor has been investigated by Tafel polarization technique. The electrochemical measurements showed that this compound is a suitable corrosion inhibitor for mild steel and the inhibition efficiency increased with inhibitor concentration. The effect of temperature on the corrosion behavior of mild steel was studied. As the temperature increases, the corrosion current density increases and the inhibition efficiency decreases. Different adsorption models were investigated and the results showed that the adsorption of this inhibitor follows the Langmuir adsorption isotherm. The values of the thermodynamic parameters were calculated by the corrosion currents at different temperatures and using the adsorption isotherm. The negative sign of Gibbs free energy indicated spontaneous adsorption of inhibitor on steel surface. Thermodynamic investigations showed that corrosion of steel X70 is exothermic and the molecules of inhibitor are adsorbed on the steel surface by the process of chemisorption and physisorption.