Advertisement

Journal of Materials Science

, Volume 29, Issue 10, pp 2801–2805 | Cite as

Formation of calcium chromate hydroxylapatite on the surface of a calcium-doped lanthanum chromite sintered body

  • I. Yasuda
  • T. Hikita
Papers

Abstract

Sintered bodies of highly sinterable calcium-doped lanthanum chromites with chromium deficiency have been found to deteriorate and form calcium chromate hydroxyl apatite on their surfaces when exposed to high-temperature water-containing atmospheres. Microstructure analysis, composition measurement, and phase identification were performed on the surface of the samples after annealing in various conditions. The mechanism of the surface deterioration is thus deduced: traces of liquid phase which are formed in the sintering process migrate to the external surface and then react with water vapour to yield an apatite-type compound. Electrical conductivity has also been measured. The poorly conductive nature of the surface will cause some problems when the subject materials are used as high-temperature electronic conductors.

Keywords

Electrical Conductivity Water Vapour Apatite Lanthanum Electronic Conductor 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    N. Sakai, T. Kawada, H. Yokokawa, M. Dokiya and T. Iwata, J. Mater. Sci. 25 (1990) 4531.CrossRefGoogle Scholar
  2. 2.
    N. Sakai, T. Kawada, H. Yokokawa and M. Dokiya, in “Proceedings of the 2nd International Symposium on Solid Oxide Fuel Cells”, Athens, July 1991, edited by F. Grosz, P. Zegers, S. C. Singhal, and O. Yamamoto (Commission of the European Communities, Luxembourg, 1991) p. 629.Google Scholar
  3. 3.
    I. Yasuda, T. Kawashima, T. Koyama, Y. Matsuzaki and T. Hikita, in “Proceedings of the International Fuel Cell Conference”, Makuhari, February 1992 (New Energy and Industrial Technology Development Organization, Tokyo Japan) p. 357.Google Scholar
  4. 4.
    V. R. Scholder and H. Schwarz, Z. Anorg. Allgem Chem. 326 (1963) 11.CrossRefGoogle Scholar
  5. 5.
    M. A. Johnson, Mineral Mag. 32 (1960) 408.Google Scholar
  6. 6.
    Z. Panek and E. Kanclir, Silikaty 20(2) (1976) 113.Google Scholar
  7. 7.
    M. Haviar, V. Figusch and G. Plesch, Sci. Sinterinq 12(2) (1980) 119.Google Scholar
  8. 8.
    N. Sakai, T. Kawada, H. Yokokawa and M. Dokiya, in “Extended Abstracts of the 17th Symposium on Solid State Ionics, Japan”, Japan, Nagoya, November 1991, p. 89.Google Scholar

Copyright information

© Chapman & Hall 1994

Authors and Affiliations

  • I. Yasuda
    • 1
  • T. Hikita
    • 1
  1. 1.Fundamental Technology Research LaboratoryTokyo Gas Co., LtdTokyoJapan

Personalised recommendations