Thiophene derivatives as corrosion inhibitors for carbon steel in hydrochloric acid solutions

Abstract

The inhibiting effect of some thiophene derivatives in 1 M HCl on the corrosion of carbon steel was studied by weight loss, potentiodynamic polarization, electrochemical frequency modulation, (EFM) and electrochemical impedance spectroscopy (EIS) techniques. The effect of temperature on the corrosion rate was investigated by the weight loss method and some thermodynamic parameters for corrosion and adsorption processes were determined and discussed. The results show that the inhibition efficiency increased with increase in inhibitor concentration and decreases with raising temperature. The adsorption of thiophene derivatives on the carbon steel surface obeys Langmuir adsorption isotherm. The obtained results indicated that the investigated compounds are physically adsorbed on the carbon steel surface. Potentiodynamic polarization studies showed that these compounds are mixed-type inhibitors and the results obtained from the different techniques are in good agreement.