New organic compounds based on siloxane moiety as corrosion inhibitors for carbon steel in HCl solution: Weight loss, electrochemical and surface studies

Abstract

The corrosion inhibition action of two new organo-silicon compounds; di-triethanolaminesiloxane and bis (dithioaminetriethanolamine) siloxane on carbon steel in 1M HCl solution was investigated using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The synthesized compounds show good inhibition efficiency and it has been found that the efficiency increases with the increase in inhibitor concentration. Polarization curves stated that the two compounds act as mixed type inhibitors and their adsorption on the metal surface followed Langmuir's adsorption isotherm. The activation parameters (Ea, ∆H°a and ∆S°a) of the dissolution process were calculated and discussed. The presence of protective inhibitor film on metal surface was confirmed by scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and X-ray diffraction (XRD) studies.