Microwave assisted fast solid state synthesis of niobates and titanates

Vaidhyanathan, B and Raizada, P and Rao, KJ (1997) Microwave assisted fast solid state synthesis of niobates and titanates. In: Journal of Materials Science Letters, 16 (24). pp. 2022-2025.

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Abstract

Niobates and titanates are a technologically important class of inorganic materials. $LiNbO_3$ (space group R3c) is ferroelectric, piezoelectric and exhibits high non-linear optic coefÆcient [1, 2]. NaNbO3 is orthorhombic and is antiferroelectric at room temperature [3]. $KNbO_3$ has a perovskite structure, exhibits three structural transitions [4] and closely resembles barium titanate. $BaTiO_3$ is a well known perovskite with many applications in industry [5]. Binary and ternary lead titanates also exhibit interesting piezoelectric, pyroelectric and optoelectronic properties [6, 7]. Synthesis of these materials based on conventional ceramic methods involves extremely long reaction times due to slow diffusion rates in the solid state. For example, (i) the conventional ceramic preparation of $LiNbO_3$ requires programmed heating [8] of the reaction mixture for 8 h at 770 K, for 3 h at 1170 K followed by a controlled slow cooling of the charge (sometimes oxygen annealing of the product for 20-30 h at 1273 K is required); (ii) synthesis of $KNbO_3$ requires 30 h of heating [9] of the reactants at 1273 K and cooling at a very slow rate; (iii) the traditional solid state preparation of $PbZr_{0.52}Ti_{0.48}O_3$ involves stepwise heating of the charge for several hours and also necessitates intermittent grinding [10].

Item Type:	Journal Article
Publication:	Journal of Materials Science Letters
Publisher:	Chapman & Hall
Additional Information:	Copyright of this article belongs to Chapman & Hall.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	25 May 2007
Last Modified:	19 Sep 2010 04:35
URI:	http://eprints.iisc.ac.in/id/eprint/10061

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