Microstructural and dielectric properties of KCl-added bismuth vanadate ceramics

Shantha, K and Varma, KBR (1997) Microstructural and dielectric properties of KCl-added bismuth vanadate ceramics. In: Journal of Materials Chemistry, 7 (8). pp. 1565-1571.

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Abstract

The effect of KCI addition on the microstructural, structural and dielectric properties of bismuth vanadate, Bi2VO5.5 (BiV) has been examined. The average grain size of BN ceramics increases with increase in KCl content (from an average grain size of TO to 80 mu m) as a result of the increased liquid-phase formation of KCI, at the grain boundaries. Differential scanning calorimetry (DSC) carried out on the KCl-added samples indicates an upward shift in the transition temperature (T-c), from 723 K (for BN) to 734 K (for 5 mol% KCl-added BiV). On further increase in the KCI content, T-c shifts down to about 722 K for 10 mol%. This trend is consistent with that of the lattice strain data. The relative permittivity as well as the dielectric loss decrease by more than half of the original values upon the addition of KCI. The relative permittivities of the KCl-added ceramics are comparable with the values predicted by the logarithmic mixture rule. Impedance analyses suggest that the grain boundary resistance of the KCl-added BiV ceramics is higher by two orders of magnitude than that of BN ceramics. The KCl-added BN ceramics exhibit ferroelectric domains and the domain density decreases as the grain boundary region is approached.

Item Type:	Journal Article
Publication:	Journal of Materials Chemistry
Publisher:	Royal Society of Chemistry
Additional Information:	Copyright of this article belongs to Royal Society of Chemistry.
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	29 Aug 2011 09:11
Last Modified:	29 Aug 2011 09:11
URI:	http://eprints.iisc.ac.in/id/eprint/38303

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