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An electron microscopic investigation of oxides related to ß-alumina

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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.

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Author notes

  1. C. N. R. Rao (Jawaharlal Nehru Visiting Professor)

    Present address: Department of Physical Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK

Authors and Affiliations

  1. Solid State and Structural Chemistry Unit, Indian Institute of Science, 560 012, Bangalore, India

    L. Ganapathi, G. N. Subbanna, J. Gopalakrishnan & C. N. R. Rao (Jawaharlal Nehru Visiting Professor)

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  1. L. Ganapathi
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  2. G. N. Subbanna
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  3. J. Gopalakrishnan
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  4. C. N. R. Rao
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Contribution No. 241 from the Solid State and Structural Chemistry Unit.

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Ganapathi, L., Subbanna, G.N., Gopalakrishnan, J. et al. An electron microscopic investigation of oxides related to ß-alumina. J Mater Sci 20, 1105–1110 (1985). https://doi.org/10.1007/BF00585755

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  • DOI: https://doi.org/10.1007/BF00585755

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