Table of Contents
ISRN Corrosion
Volume 2012, Article ID 971650, 6 pages
http://dx.doi.org/10.5402/2012/971650
Research Article

Naturally Occurring Elettaria cardamomum Extract as a Corrosion Inhibitor for the Dissolution of Zinc in 1.0 M HCl

Department of Chemistry, Faculty of Science, Benha University, Benha 13518, Egypt

Received 21 September 2012; Accepted 8 October 2012

Academic Editors: N. Boshkov, I. Obot, and Q. Qu

Copyright © 2012 M. Sobhi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The inhibitive action of water extract of naturally occurring Elettaria cardamomum plant against the corrosion of zinc in 1.0 M HCl solution was investigated using weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy. From these measurements, it was found that the values of surface coverage (θ) and inhibition efficiency increase with increasing the concentration of the extracted compound. The activation energy of the corrosion was calculated and it was found that the presence of the extracted compound in 1.0 M HCl solutions increases the values of activation energy. The inhibiting effect of this extract results from its adsorption on the electrode surface via the adsorption centers of the compounds present in the extract. The adsorption of this extract compound onto the surface of zinc follows the Langmuir adsorption isotherm. The thermodynamic parameters were calculated for the tested system from the data obtained at different temperatures.