Preparation of $BaTi_4O_9$ and $Ba_2Ti_9O_{20}$ ceramics by the wet chemical gel-carbonate method and their dielectric properties

Kumar, Sanjiv and Raju, VS and Kutty, TRN (2007) Preparation of $BaTi_4O_9$ and $Ba_2Ti_9O_{20}$ ceramics by the wet chemical gel-carbonate method and their dielectric properties. In: Materials Science and Engineering: B, 142 (2-3). pp. 78-85.

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Abstract

Preparation of $BaTi_4O_9$ and $Ba_2Ti_9O_{20}$ ceramics by the wet chemical gel-carbonate method, and their microstructural and dielectric properties are presented. Monophasic $Ba_2Ti_9O_{20}$ of triclinic symmetry having high dielectric constant $({\epsilon}_r \sim$ 52 at 1 MHz), low temperature coefficient of dielectric constant $(\tau_ \epsilon \sim 6 ppm/ ^ \circ C)$ and moderate quality factor (Q > 2000) could be realized on sintering at $1300^ \circ C$. These ceramics are prepared by using Ba and Ti compounds in 1:4.5 molar ratio in the reaction. But phase singular $BaTi_4O_9$ ceramics could not be synthesized by this method. The sintered ceramics obtained when Ba and Ti compounds are in 1:4 molar ratio, are associated with Ba4Ti13O30 phase that impart higher τvar epsilon values. However by using Ba and Ti compounds in 1:4.1 molar ratio, sintered ceramics containing $BaTi_4O_9$ as well as $Ba_2Ti_9O_{20}$ could be prepared. Such ceramics possess intermediate dielectric properties with $\epsilon_r, \tau_ \epsilon$ and Q being $23-50, \geq 4 ppm/^ \circ C$ and \geq 2000, respectively. The dielectric properties of the ceramics depend considerably on sintering temperature and their microstructure.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Barium tetratitanate;Barium nonatitanate;Wet chemical method;Dielectric resonator;Microstructure. Division of Chemical Sciences > Materials Research Centre 23 Jul 2008 19 Sep 2010 04:41 http://eprints.iisc.ernet.in/id/eprint/12543