Effect of Thiazole Derivatives on the Corrosion of Mild Steel in 1 M HCl Solution

Corrosion inhibition of carbon steel in normal hydrochloric acid solution at 303 K by new thiazole derivatives has been studied by a series of known techniques such as weight loss, polarisation and electrochemical impedance spectroscopy (EIS). The experimental results have showed that this organic compound revealed a good corrosion inhibition and that the inhibition efficiency is increased with the inhibitor concentration. Potentiodynamic polarisation suggested that it is a mixed type of inhibitor. Impedance measurements showed that the double-layer capacitance decreased and charge-transfer resistance increased with increase in the inhibitors concentration and hence increasing in inhibition efficiency. The adsorption of thiazole on the carbon steel surface, in 1 M HCl solution, obeyed to the Langmuir isotherm with a very high negative value of the standard Gibbs free energy of adsorption A G °ads (chemisorption).