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Oxidation of Metals

, Volume 9, Issue 5, pp 415–425 | Cite as

Study of the oxidation kinetics of vanadium carbide

  • C. Santafé
  • C. Borgianni
Article

Abstract

The oxidation of an oxycarbide of vanadium, VO0.6C0.7, and of a vanadium carbide, VC0.98, was studied athermally up to temperatures of 800° C and isothermally between 400 and 580° C at oxygen pressures ranging from 10−2 to 1 atm. The oxycarbide followed the parabolic rate law below 450° C with V2O5 forming as the only reaction product. The activation energy was 49 kcal/mole. VC0.98 did not form an oxide in this temperature range, but rather dissolved oxygen, the activation energy being 26.6 kcal/mole. No oxygen pressure dependence on the kinetics was found for either sample in this temperature range. Both samples followed the cubic rate law during oxidation in the range of 500–580° C during which V2O5 formed. There was a P1/3 dependence and the activation energy was the same for both materials, 51 kcal/mole. The cubic rate law and the positive pressure dependency (rather than an anticipated negative dependency) were attributed to an electric field associated with oxygen ions chemisorbed on a thin layer of V2O5.

Key words

vanadium carbide vanadium oxycarbide oxidation parabolic rate law cubic rate law chemisorption 

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References

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    C. Borgianni, V. Di Stefano, and R. Grimaldi,J. Less-Common Met. 20, 299 (1970).Google Scholar
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    P. Kofstad,High Temperature Oxidation of Metals (John Wiley & Sons, New York, 1968).Google Scholar
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    W. J. Moore and J. K. Lee,Trans. Faraday Soc. 47, 501 (1951).Google Scholar
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    H. J. Engell and K. Hauffe,Metallwirtsch. 6, 285 (1952).Google Scholar

Copyright information

© Plenum Publishing Corporation 1975

Authors and Affiliations

  • C. Santafé
    • 1
  • C. Borgianni
    • 1
  1. 1.Centro Sperimentale MetallurgicoSPARomeItaly

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