RESEARCH ARTICLE

 

Inhibitor for the corrosion of mild steel in H₂SO₄

 

 

Niketan S. Patel; Smita Jauhari; Girishkumar N. Mehta

Chemistry Section, Applied Sciences and Humanities Department, Sardar Vallabhbhai National Institute of Technology, Surat-395007, Gujarat, India

 

 

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ABSTRACT

An extract of Terminalia chebula fruits was investigated as a corrosion inhibitor of mild steel in 0.5 M H₂SO₄ by means of conventional mass loss, electrochemical polarization, electrochemical impedance spectroscopy and scanning electron microscopy. The mass loss results showed that the extract of Terminalia chebula is an excellent corrosion inhibitor, electrochemical polarization data revealed the mixed mode of inhibition and the results of electrochemical impedance spectroscopy showed that the change in the impedance parameters, charge transfer resistance and double layer capacitance with the change in concentration of the extract is due to the adsorption of active molecules leading to the formation of a protective layer on the surface of mild steel. Scanning electron microscopic studies provided confirmatory evidence of an improved surface condition, due to adsorption, for corrosion protection.

Keywords: Terminalia chebula, acid corrosion inhibitor, electrochemical polarization, electrochemical impedance spectroscopy, mild steel

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Acknowledgements

The authors thank Dr P.D. Porey, Director, and Dr M.N. Mehta, Head of the Applied Sciences and Humanities Department, Sardar Vallabhbhai National Institute of Technology, Surat, for the scholarship, encouragement and facilities.

 

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Received 6 April 2009
Revised 27 October 2009
Accepted 27 October 2009

 

 

* To whom correspondence should be addressed. E-mail: niketan.ptl@gmail.com