Journal :   Asian Journal of Research in Chemistry

Volume No. :   5

Issue No. :  3

Year :  2012

Pages :   390-396

ISSN Print :  0974-4169

ISSN Online :  0974-4150


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Corrosion Inhibition and Adsorption Properties of African marigold for the Corrosion of Mild Steel in Hydrochloric acid



Address:   Dr. R. Subha1* and Dr. R. Saratha2
1Assistant Professor, Department of Chemistry, Sri Sakthi Institute of Engineering and Technology, Coimbatore -62.
2Associate Professor, Department of Chemistry, Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore-43.
*Corresponding Author
DOI No:

ABSTRACT:
Inhibitive and adsorption properties of acid extract of flowers of African marigold (AMF) for the corrosion of mild steel in hydrochloric acid medium was studied using weight loss and electrochemical studies. The results revealed that acid extract of African marigold flowers inhibited the corrosion of mild steel. The inhibition efficiency of the extract increases with increase in concentration of the extract, exposure time and temperature of the medium. The maximum inhibition efficiency of 97% was obtained at 0.3%v/v concentration of the extract at room temperature. Potentiodynamic polarization study clearly reveals that the extract controls both anodic as well as cathodic reactions. Double layer capacitance (Cdl) and charge transfer resistance (Rct) values were derived from Nyquist plots. The adsorption of extract components on the mild steel surface was found to follow the Langmuir adsorption isotherm. The energy of activation, enthalpy of activation and entropy of activation for the dissolution process were determined and discussed. A mechanism of adsorption of the flower components on the surface of the metal was proposed for the inhibition behavior on the basis of FTIR study.
KEYWORDS:
Corrosion rate, inhibition efficiency, Potentiodynamic polarization, FTIR, adsorption isotherm.
Cite:
R. Subha, R. Saratha. Corrosion Inhibition and Adsorption Properties of African marigold for the Corrosion of Mild Steel in Hydrochloric acid. Asian J. Research Chem. 5(3): March 2012; Page 390-396.
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