Electrochemical, Activations and Adsorption Studies for the Corrosion Inhibition of Low Carbon Steel in Acidic Media

The effect of phenylthiourea as a corrosion inhibitor for low carbon steel at different hydrochloric acid concentrations, different temperatures and fixed speed of electrode rotation, were addressed in this work. Polarization technique was used to evaluate the corrosion rates parameters. The corrosion rate of low carbon steel increases with temperature and follows Arrhenius equation in all acid concentrations in presence and absence of the inhibitor. Detailed thermodynamic parameters of activation (Delta H-act and Delta S-act) for the corrosion reaction were obtained using nonlinear estimation method, while adsorption parameters (Delta G(ads), Delta H-ads and Delta S-ads) were obtained using graphical method. Maximum inhibitor efficiency was (96.44%) obtained at 1 M HCl at 333 K and 1 g/L inhibitor concentration.