Inhibition of mild steel corrosion in presence of fatty acid imidazolines in hydrochloric acid

Abstract

The corrosive behavior of mild steel in 1M HCl solutions containing selected imidazolines of fatty acids with C7-C17 was investigated using weight-loss method, potentiodynamic polarization technique and scanning elecron microscopy. The results obtained revealed that all the studied imidazolines are effective in reducing corrosion of mild steel in HCl media. The adsorption of the inhibitors on the mild steel surface obeys Langmuir’s adsorption isotherm. The thermodynamic parameters of adsorption deduced reveal a strong interaction and spontaneous adsorption of inhibitors on the mild steel surface. The influence of inhibitor concentration, solution temperature, immersion time and acid concentration on the corrosion of mild steel has also been investigated. Scanning electron microscopy(SEM) of mild steels samples is performed to show adsorption of inhibitors on metal surface. Potentiodynamic polarization data showed that the compounds studied are mixed type inhibitors in the acid solution.