Investigation of the inhibitive effect of some quinoxaline compounds on the corrosion of steel in HCl solution

 

M. Benabdellah1, R. Touzani1,2, A. Aouniti1, A. Dafali1, S. Elkadiri1,

B. Hammouti1*, M. Benkaddour3

1 Laboratoire de Chimie Appliquée et Environnement, Faculté  des Sciences, Oujda, Morocco

2 Faculté Pluridisciplinaire de Nador, Université Mohammed 1er,  B.P. 300, 62700 Selouane, Nador, Morocco3

3 Laboratoire d’Analyse et  de Caractérisation des Matériaux, Faculté des Sciences, Oujda, Morocco

* Corresponding author. E-mail: hammoutib@yahoo.fr

Received: 28 June 2006; revised version accepted: 28 May 2007

 

Abstract

     The corrosion inhibition of steel in 1M hydrochloric acid solution by some quinoxaline compounds has been studied using weight loss and electrochemical (ac impedance and dc polarisation) techniques. All the employed measurements are in reasonable agreement. All measurements show that inhibition efficiencies increase with increase in inhibitor concentration. This reveals that inhibitive actions of inhibitors were mainly due to adsorption on steel surface. Polarization curves show that the used compounds are essentially cathodic type inhibitors. The variation in inhibition efficiency values depends on the type of functional groups substituted on benzene ring. It was found that the presence of chlorine atoms in the molecular structure of studied molecules facilitate the adsorption of molecule on steel surface. Adsorption of these inhibitors follows Langmuir adsorption isotherm. Thermodynamic parameters of adsorption (Kads, ?Gads) of studied inhibitors were calculated using Langmuir adsorption isotherm.

 

Keywords: Quinoxaline; Steel; acid; Corrosion; inhibition; Adsorption.

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