Preparation and characterization of rubidium-beta-alumina by the gel-to-crystallite conversion method

Jayaraman, V and Periaswami, G and Kutty, TRN (2000) Preparation and characterization of rubidium-beta-alumina by the gel-to-crystallite conversion method. In: Materials Research Bulletin, 35 (8). 1213 -1225.

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Abstract

Preparation of Rb-beta -alumina was realized by the gel-to-crystallite conversion method. Reaction of hydrated aluminum hydroxide gel with RbOH in ethanol medium gave rise to the Rb+-inserted pseudoboehmite precursor under wet chemical conditions. The thermal decomposition of the precursor yielded Rb-beta -alumina. The Rb2O:Al2O3 ratio of monophasic Rb-beta -alumina ranged from 1:10 to 1:22. The extended stability in the compositional range is due to the fact that the conduction planes containing Rb+ and O2- ions can have lower occupancy of Rb+ ions for larger sized alkali ions, permitting the steric separation of the adjoining spinel blocks. High-resolution electron microscopy revealed that the decreasing occupancy of alkali ions in the conduction plane is balanced by changing widths of spinel blocks arising from the shift of tetrahedral Al3+ ions to octahedral sites and an accompanying increase in stacking defects. (C) 2000 Elsevier Science Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	Materials Research Bulletin
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	A.Oxides; B.Chemical synthesis; C.Electron microscopy; D. Defects.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	09 Sep 2010 12:12
Last Modified:	19 Sep 2010 06:16
URI:	http://eprints.iisc.ac.in/id/eprint/32096

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