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Synergistic Inhibition of Corrosion of Carbon Steel by the Ternary Formulations containing Phosphonate, Zn (II) and Ascorbic Acid

Author Affiliations

  • 1 Department of Chemistry, National Institute of Technology (NIT) Warangal-506004, Andhra Pradesh, INDIA

Res. J. Recent Sci., Volume 1, Issue (ISC-2011), Pages 93-98, (2012)


Studies on corrosion inhibition of carbon steel in low chloride aqueous environment using ternary inhibitor formulations based on phosphonates namely 1-Hydroxyethane-1,1-diphosphonic acid (HEDP) and Nitrilotris(methylenephosphonic acid) (NTMP) are presented. From these studies, an environmentally friendly organic compound namely ascorbic acid (AA) is proved to be an excellent synergist to the binary inhibitor formulations, HEDP - Zn2+ and NTMP - Zn2+ in corrosion control of carbon steel. Gravimetric studies infer that the required minimum concentrations of both the phosphonate as well as zinc ions for good corrosion inhibition could significantly be reduced by the addition of ascorbic acid. The minimum concentration of Zn2+ required for effective inhibition in case of HEDP – Zn2+ - AA and NTMP - Zn2+ - AA are 15 ppm and 20 ppm respectively. Further, still lower concentrations of Zn2+ are sufficient for the maintenance of the protective film in case of both the inhibitor formulations. Studies on effect of pH on corrosion inhibition indicate that both the ternary inhibitor formulations are effective in corrosion control in wide pH ranges. HEDP - Zn2+ - AA is effective in the pH range 5.0 to 9.0 and NTMP - Zn2+ - AA is effective in the pH range 4.0 to 10.0.


  1. Felhosi I., Keresztes Zs., Karman F.H., Mohai M., Bertoti I. and Kalman E. Effects of bivalent cations on corrosion inhibition of steel by 1-hydroxyethane-1,1-diphosphonic acid, J. Electrochem. Soc., 146, 961 – 969 (1999)
  2. Gonzalez Y., Lafont M.C., Pebere N. and Moran F.A synergistic effect between zinc salt and phosphonic acid for corrosion inhibition of a carbon steel, J. Appl. Electrochem., 26, 1259 – 1265 (1996)
  3. Telegdi J., Shaglouf M.M., Shaban A., Karman F.H., Betroti I., Mohai M. and Kalman E., Influence of cations on the corrosion inhibition efficiency of aminophosphonic acid, Electrochim. Acta, 46, 3791 – 3799 (2001)
  4. Demadis K.D., Mantzaridis C., Raptis R.G. and Mezei G. Metal–organotetraphosphonate inorganic–organic hybrids: Crystal structure and anticorrosion effects of zinc hexamethylenediaminetetrakis (methylene -phosphonate) on carbon steels, Inorg. Chem., 44, 4469 – 4471 (2005)
  5. Pech-Canul M.A. and Chi-Canul L.P., Investigation of the inhibitive effect of N-phosphono-methyl-glycine on the corrosion of carbon steel in neutral solutions by electrochemical techniques, Corrosion, 55, 948 – 956 (1999)
  6. Amar H., Benzakour J., Derja A., Villemin D., Moreau B., Braisaz T. and Tounsi A., Synergistic corrosion inhibition study of Armco iron in sodium chloride by piperidin-1-yl-phosphonic acid – Zn2+ system, Corros. Sci., 50, 124 – 130 (2008)
  7. Kalman E. Proc. 7th European Symposium on Corrosion Inhibitors (7SEIC), Ann. Univ. Ferrara, N.S., Sez. V2, 745 (1990)
  8. Appa Rao B.V. and Christina K. Ternary inhibitor system containing phosphonate, molybdate and Zn2+ in corrosion control of carbon steel, Indian J. Chem. Technol., 13, 275 – 282 (2006)
  9. Appa Rao B.V., Venkateswara Rao M., Srinivasa Rao S. and Sreedhar B. Tungstate as a synergist to phosphonate-based formulation for corrosion control of carbon steel in nearly neutral aqueous environment, J. Chem. Sci., 122, 639 – 649 (2010)
  10. Mathiyarasu J., Natarajan R., Palaniswamy N. and Rengaswamy N.S. Synergistic effect of citrate ethylene diamine phosphonic acid and Zn2+ on the inhibition of corrosion of mild steel in low chloride media, Bull. Electrochem., 13, 161 – 165 (1997)
  11. Kalman E., Varhegyi B., Bako I., Felhosi I., Karman F.H. and Shaban A., Corrosion inhibition by 1-Hydroxy-ethane-1,1-diphosphonic Acid, J. Electrochem. Soc., 141, 3357 – 3360 (1994)
  12. Reznik L.Y., Sathler L., Cardoso M.J.B. and Albuquerque M.G. Experimental and theoretical structural analysis of Zn(II)-1-hydroxyethane-1,1-diphosphonic acid corrosion inhibitor films in chloride ions solution, Mater. Corros., 59, 685–690 (2008)
  13. Awad H.S. Surface examination and analysis of steel inhibited by 1-hydroxyethylidene-1,1-diphosphonic acid in presence of zinc ions, Corros. Eng. Sci. Technol., 40, 57–64 (2005)
  14. Gonzalez Y., Lafont M.C., Pebere N., Chatainier G., Roy J. and Bouissou T. A corrosion inhibition study of a carbon steel in neutral chloride solutions by zinc salt/phosphonic acid association, Corros. Sci., 37, 1823 – 1837 (1995)
  15. Demadis K.D., Katarachia S.D. and Koutmos M. Crystal growth and characterization of zinc–(amino-tris-(methylenephosphonate) organic-inorganic hybrid networks and their inhibiting effect on metallic corrosion, Inorg. Chem. Commun., 8, 254–258 (2005)
  16. Gopi D., Manimozhi S., Govindaraju K.M., Manisankar P. and Rajeswari S. Surface and electrochemical characterization of pitting corrosion behavior of 304 stainless steel in ground water media, J. Appl. Electrochem., 37, 439–449 (2007)
  17. Ashcraft A., Bohnsack G., Holm R., Kleinstueck R. and Strop S. Mechanism of Corrosion Inhibition and Transition to Underdeposit Corrosion, Mater. Perform., 27 (2), 31 – 37 (1988)
  18. Appa Rao B.V. and Srinivasa Rao S. Synergistic role of ascorbate in corrosion inhibition, Bull. Electrochem., 21(3), 139–144 (2005)
  19. Appa Rao B.V., Srinivasa Rao S. and Sarath Babu M. Synergistic effect of NTMP, Zn2+ and ascorbate in corrosion inhibition of carbon steel, Indian J. Chem. Technol., 12, 629 – 634 (2005)
  20. Appa Rao B.V., Srinivasa Rao S. and Venkateswara Rao M. Environmentally friendly ternary inhibitor formulation based on N, N-bis(phosphonomethyl) glycine, Corros. Eng. Sci. Technol., 43(1), 46 – 53 (2008)
  21. Appa Rao B.V. and Srinivasa Rao S. Electrochemical and surface analytical studies of synergistic effect of phosphonate, Zn2+ and ascorbate in corrosion control of carbon steel, Mater. Corros., 61(4), 285 – 301 (2010)
  22. Singley J.E., Beaudet B.A., Markey P.H., DeBerry D.W., Kidwell J.R. and Malish D.A. Corrosion Monitoring and Treatment. In: Corrosion prevention and control in water treatment and supply systems. Noyes Publications, 34 – 50 (1985)
  23. ASTM Standard G 31-72, ‘Standard Practice for Laboratory Immersion Corrosion Testing of Materials’ (Reapproved 1990) Annual Book of ASTM Standards, 0302 (Philadelphia, PA:ASTM) (1990)
  24. Freeman R.A. and Silverman D.C. Error Propagation in Coupon Immersion Tests, Corrosion, 48(6), 463 – 466 (1992)