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


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.


Ferrite Barium Gallate Borate Alkali Metal 
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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

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