Abstract
In the present investigation a triazole derivative, 4-{(E)-[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-5-(pyridin-4-yl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (HMPT) has been synthesized. The inhibition efficacy of HMPT has been studied on carbon steel in 1 M hydrochloric acid solution by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization techniques (PDP), electrochemical frequency modulation (EFM), and linear polarization resistance (LPR) techniques. The results revealed that HMPT has significant inhibitory effects for the corrosion of carbon steel in an acid medium and displayed around 95% inhibition efficiency at optimum HMPT concentration with decrease in the current density value from 279.9 mu A/cm(2) to 153.8 mu A/cm(2). PDP studies signified mixed-type inhibition of HMPT. The mechanism of inhibition is believed to be occur by the adsorption of HMPT on the carbon steel surface and obeyed Langmuir adsorption isotherm. The values of Gibbs free energy of adsorption indicated that the adsorption of HMPT molecules on carbon steel takes place by both physical and chemical adsorption processes. The SEM/EDX studies confirmed the adsorption of HMPT on the carbon steel surface. The quantum chemical studies have provided good support to the experimental results. The promising results indicate the proposed inhibitor HMPT as a possible corrosion inhibitor for protecting the metallic components effectively from corrosion.