Materials Transactions Online

Materials Transactions, Vol.50 No.11 (2009) pp.2656-2663
© 2009 The Japan Institute of Metals

The Effect of Water Vapor on High Temperature Oxidation of Fe-Cr Alloys at 1073 K

Mohd Hanafi Bin Ani, Toshiya Kodama, Mitsutoshi Ueda, Kenichi Kawamura and Toshio Maruyama

Department of Metallurgy and Ceramics Sciences, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8552, Japan

The effect of water vapor on high temperature oxidation was studied based on Wagner's theory of binary alloy oxidation. The oxidation of Fe-Cr alloys was carried out at 1073 K in dry and humid conditions. The oxidation was conducted in a closed apparatus at 1073 K and the oxygen partial pressure of 1.1 × 10-14 Pa, which was fixed by a Fe/FeO buffer. To prepare the humid condition, Ar-5% H2 gas mixture of 3 × 104 Pa was filled in the apparatus, which provided the water vapor pressure of 3.3 × 102 Pa. The transition of internal and external oxidation was observed in Fe-8Cr in the dry condition and in Fe-12Cr in the humid condition.
Interdiffusion experiment of Fe/Fe-16Cr diffusion couples in dry and humid environments showed that the diffusion coefficient of Cr was not influenced by dissolved hydrogen.
The oxygen permeability in α-Fe was determined by means of internal oxidation of Fe-5Cr alloy at 1073 K and the oxygen partial pressure of 1.1 × 10-14 Pa in a dry and two humid conditions with water vapor of 1.1 × 102 Pa and 3.3 × 102 Pa. The oxygen permeability in humid condition increases by a factor of 1.4. Dissolved hydrogen increases the oxygen permeability, thus increases the minimum concentration of Cr to form external scales in humid conditions. The presence of dissolved hydrogen changes the oxide shape from discrete spherical particle to spike-like precipitates, which enhances the oxygen transport along the metal/oxide precipitates interface.

(Received 2009/6/22; Accepted 2009/8/27; Published 2009/10/25)

Keywords: steam oxidation, internal oxidation, external oxidation

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REFERENCES

  1. M. Sato, M. Yaguchi, Y. Tanaka, J. Iwasaki, M. Fukuda, E. Saito, H. Nakagawa, A. Shiibashi and S. Izumi: Karyoku Genshiryoku Hatsuden 57 (2006) 821–838. (in Japanese)
  2. J. Zurek, M. Michalik, F. Schmitz, T. U. Kern, L. Singheiser and W. J. Quadakkers: Oxidation of Metals 63 (2005) 401–422.
  3. K. Segerdahl, J. E. Svensson and L. G. Johansson: J. Electrochem. Soc. 151 (2004) B394–B398.
  4. C. T. Fujii and R. A. Meussner: J. Electrochem. Soc. 111 (1964) 1215–1221.
  5. H. Asteman, K. Segerdahl, J. E. Svensson, L. G. Johansson, M. Halvarsson and T. E. Tang: Mater. Sci. Forum 461–464 (2004) 775–782.
  6. A. Yamauchi, K. Kurokawa and H. Takahashi: Oxidation of Metals 59 (2003) 517–527.
  7. K. Segerdahl, J. E. Svensson and L. G. Johansson: Mater. Corrosion 53 (2002) 247–255.
  8. C. Wagner: Zeitschrift für Elektrochemie 63 (1959) 772–782.
  9. R. A. Rapp: Acta Metall. 9 (1961) 730.
  10. O. Kubaschewski: Iron Binary Phase Diagrams, (Springer-Verlag, Berlin, 1982).
  11. M. Nugamo: Zairyo-to-Kankyo 53 (2004) 548–553. (in Japanese)
  12. H. Yamada, Y. Hattori, N. Komai, T. Sato, H. Oohira and T. Yanagisawa: Karyoku Genshiryoku Hatsuden 52 (2001) 1217–1231. (in Japanese)
  13. I. Barin: Thermochemical Data of Pure Substances, (VHC Publisher, Vol.4, 1991).
  14. H. Oikawa: Tetsu to Hagane 68 (1982) 1489–1497. (in Japanese)
  15. J. Takada, S. Yamamoto, S. Kikuchi and M. Adachi: Metall. Trans. A 17A (1986) 221–229.
  16. J. Takada, S. Yamamoto, S. Kikuchi and M. Adachi: Oxidation of Metals 25 (1986) 93–105.
  17. S. Hayashi and T. Narita: J. Japan Inst. Metals 63 (1999) 1204–1211. (in Japanese)
  18. J. Takada and M. Adachi: J. Mater. Sci. 21 (1986) 2133–2137.
  19. F. H. Stott, G. C. Wood, D. P. Whittle, B. D. Bastow, Y. Shida and A. Martinez-Villafane: Solid State Ionics 12 (1984) 365–374.
  20. D. P. Whittle, Y. Shida, G. C. Wood, F. H. Stott and B. D. Bastow: Philos. Mag. A 46 (1982) 931–949.
  21. F. H. Stott and G. C. Wood: Mater. Sci. Technol. 4 (1988) 1072–1078.
  22. S. Goto and S. Koda: J. Japan Inst. Metals 34 (1970) 319–326. (in Japanese)


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