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Relationship between the sodium oxide activity of ceramic (Na-β + β)-alumina and the sodium activity in the ambience of the material

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Published/Copyright: February 7, 2022
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Abstract

By means of a solid state electrochemical method, the activity of sodium oxide dissolved in various samples of ceramic Na-(β + β″)-alumina was measured as a function of the composition of the ceramics, with the independent variable being adjusted by the sodium activity in the ambience. Taking into account all the relevant findings, the lgaNa2O vs. lg  a Na relationship can quantitatively be described by a polynomial of third degree with respect to lg  a Na . The gradual change of the sodium oxide activity indicates that the thermodynamic behaviour of the material is mainly determined by the occurrence of nonstoichiometric phases with easy transitions from one stoichiometry to the other one.


Dr. H. Näfe Max-Planck-Institut für Metallforschung Heisenbergstr. 3, D-70569 Stuttgart, Germany Tel.: +49 711 689 3113 Fax: +49 711 689 3131

  1. The author is very grateful to F. Meyer, S. Gollhofer, R. Subasri, and K. Shqau for their technical assistance during the course of this work.

References

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[4] H. Näfe: J. Am. Ceram. Soc., to be submitted.Search in Google Scholar

Received: 2003-05-27
Published Online: 2022-02-07

© 2003 Carl Hanser Verlag, München

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