Thermal expansion behaviour of barium and strontium zirconium phosphates

Tantri, Srikari P and Geetha, K and Umarji, AM and Ramasesha, Sheela K (2000) Thermal expansion behaviour of barium and strontium zirconium phosphates. In: Bulletin of Materials Science, 23 (6). pp. 491-494.

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Abstract

Ba1.5-xSrxZr4P5SiO24 compounds with x = 0, 0.25, 0.5, 0.75, 1.0, 1.25 and 1.5, belonging to the low thermal expansion NZP family were synthesized by the solid state reaction method. The XRD pattern could be completely indexed with respect to R (3) over bar space group indicating the ordering of vacancy at the divalent cation octahedral sites. The microstructure and bulk thermal expansion coefficient from room temperature to 800 degreesC of the sintered samples have been studied. All the samples show very low coefficient of thermal expansion (CTE), with x = 0 samples showing negative expansion. A small substitution of strontium in the pure barium compound changes the sign of CTE, Similarly, x = 1.5 sample (pure strontium) shows a positive CTE and a small substitution of barium changes its sign, X = 1.0 and 1.25 samples have almost constant CTE over the entire temperature range. The low thermal expansion of these samples can be attributed to the ordering of the ions in the crystal structure of these materials.

Item Type:	Journal Article
Publication:	Bulletin of Materials Science
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright for this article belongs to Indian Academy of Sciences.
Keywords:	Coefficient of thermal expansion;low thermal expansion;NZP;ceramic;dilatometer;anisotropy
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	09 Sep 2004
Last Modified:	19 Sep 2010 04:16
URI:	http://eprints.iisc.ac.in/id/eprint/1954

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