Volume : 5, Issue : 8, August - 2016

Inhibition of Zinc Corrosion in Hydrochloric Acid by Some Ligands and Complexes

A. S. M. Diab, Abdou Saad El Tabl, H. M. Osman

Abstract :

<p>The corrosion inhibition of zinc in 2M HCl solution by thiourea , ligands , and complexes has been studied with respect to their concentrations. The corrosion rates were measured by using gasometric technique. The inhibition efficiency of each inhibitor increases and decreases with increasing its concentration in the range of, inhibition action and missing inhibition action respectively. Zinc surface coverage (&theta;) could be obtained from the corrosion rates in 2M HCl solution in absence and presence the used additives by gasometric technique. The inhibitors appear to function through adsorption following langmuir‘s isotherm. The free energy change of adsorption (&Delta;Gads.), enthalpy change (&Delta;Hads.), entropy change(&Delta;S), and activation engry(Ea) associated with each inhibitor have been determined. The heat of adsorption (&Delta;Hads.) and free energy of adsorption (&Delta;Gads.) of all inhibitors are negative values</p>