Advertisement

Journal of Materials Science

, Volume 20, Issue 3, pp 1105–1110 | Cite as

An electron microscopic investigation of oxides related to ß-alumina

  • L. Ganapathi
  • G. N. Subbanna
  • J. Gopalakrishnan
  • C. N. R. Rao
Papers

Abstract

High resolution electron microscopic (HREM) investigation of potassiumβ-alumina and the related gallate and ferrite has revealed that whereas the aluminate and gallate are highly disordered, consisting of random sequence ofβ andβ″ units, the ferrite is more ordered. The aluminate and gallate are sensitive to electron beam irradiation exhibiting beam-induced damage similar to sodiumβ″-alumina. Significantly, the ferrite is beamstable, the difference in behaviour amongst these related oxides arising from the different mechanisms by which alkali metal nonstoichiometry is accommodated. Barium hexaaluminate and hexaferrite are both highly ordered; specimens prepared by the barium borate flux method exhibit a new √3a×√3a superstructure of the hexagonal magnetoplumbite cell.

Keywords

Ferrite Barium Gallate Borate Alkali Metal 
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.
    W. L. Bragg, C. Gottfried andJ. West,Z. Kristallogr. 77 (1931) 255.Google Scholar
  2. 2.
    C. R. Peters, M. Bettman, J. W. Moore andJ. D. Glick,Acta Crystallogr. B27 (1971) 1826.Google Scholar
  3. 3.
    R. Collongues, J. Thery andJ. P. Boilot, in “Solid Electrolytes”, edited by P. Hagenmuller and W. Van Gool (Academic Press, New York, 1978) P.253.Google Scholar
  4. 4.
    G. C. Farrington andJ. L. Briant,Science 204 (1979) 1371.Google Scholar
  5. 5.
    D. J. M. Bevan, B. Hudson andP. T. Moseley,Mater. Res. Bull. 9 (1974) 1073.Google Scholar
  6. 6.
    H. Sato andY. Hirotsu,ibid. 11 (1976) 1307.Google Scholar
  7. 7.
    L. C. De Jonghe,J. Mater. Sci. 12 (1977) 497.Google Scholar
  8. 8.
    J. O. Bovin,Nature (London) 273 (1978) 136.Google Scholar
  9. 9.
    Idem, Acta Crystallogr. A35 (1979) 572.Google Scholar
  10. 10.
    V. Adelskold,Arkiv Kemi. Min. Geol. 12A (1938) 1.Google Scholar
  11. 11.
    P. B. Braun,Philips Res. Rep. 12 (1957) 491.Google Scholar
  12. 12.
    K. Kuwabara andT. Takahashi,J. Solid State Chem 19 (1976) 147.Google Scholar
  13. 13.
    J. O. Bovin andM. O'keeffe,ibid. 33 (1980) 37.Google Scholar
  14. 14.
    G. J. Dudley, B. C. H. Steele andA. T. Howe,ibid. 18 (1976) 141.Google Scholar
  15. 15.
    Y. Matsui andS. Horiuchi,Acta Crystallogr. A37 (1981) 51.Google Scholar
  16. 16.
    N. Iyi, S. Takekawa, Y. Bando andS. Kimura,J. Solid State Chem. 47 (1983) 34.Google Scholar
  17. 17.
    L. Ganapathi, J. Gopalakrishnan andC. N. R. Rao,Mater. Res. Bull. 19 (1984) 669.Google Scholar

Copyright information

© Chapman and Hall Ltd 1985

Authors and Affiliations

  • L. Ganapathi
    • 1
  • G. N. Subbanna
    • 1
  • J. Gopalakrishnan
    • 1
  • C. N. R. Rao
    • 1
  1. 1.Solid State and Structural Chemistry UnitIndian Institute of ScienceBangaloreIndia

Personalised recommendations