J Mater Sci Technol ›› 2011, Vol. 27 ›› Issue (12): 1143-1149.

• Iron and Steel • Previous Articles     Next Articles

Seed Extract of Psidium guajava as Ecofriendly Corrosion Inhibitor for Carbon Steel in Hydrochloric Acid Medium

K.P.Vinod Kumar1), M. Sankara Narayana Pillai2) , G. Rexin Thusnavis3)   

  1. 1) Department of Chemistry, University College of Engineering, Nagercoil, Anna University of Technology, Tirunelveli, Nagercoil-629004, Tamil Nadu, India
    2) Department of Chemistry, Noorul Islam University, Kumaracoil, Nagercoil, Tamilnadu, India
    3) Department of Chemistry, St. Xavier0s Catholic College of Engineering, Chunkankadai, Nagercoil-629003, Tamil Nadu, India
  • Received:2011-06-13 Revised:2011-08-19 Online:2011-12-28 Published:2011-12-24
  • Contact: K.P.V. Kumar

Abstract: The anticorrosion characteristics of the seeds of Psidium guajava (P. guajava) fruits on carbon steel in acid medium were examined with weight loss data and subsequently thermodynamic factors such as heat of adsorption of the inhibitor on the metal surface (Q), change in entropy (?S), change in free energy of the reaction (?G), corrosion rate (CR) and energy of activation for corrosion reaction of carbon steel (E) were also evaluated. Adsorption isotherm was plotted to study the adsorption of the inhibitor on the metal surface with increasing concentration of the inhibitor. The functional groups responsible for inhibition were investigated using Fourier transform infrared (FT-IR) spectra. Electrochemical parameters were evaluated through the potentiodynamic Tafel polarization and impedance spectral studies. Scanning electron microscopy (SEM) micrographs were recorded to investigate the change in surface morphology. The complete study reveals the effciency of seed extract of P. guajava as a safe, ecofriendly and alternate corrosion inhibitor for carbon steel
in acid medium.

Key words: Psidium guajava (P: guajava), Steel, Corrosion, Polarization, Impedance, Ecofriendly