Open Access Nano Express

Crystal structure and electrical properties of bismuth sodium titanate zirconate ceramics

Ampika Rachakom1, Panupong Jaiban1, Sukanda Jiansirisomboon12 and Anucha Watcharapasorn12*

Author affiliations

1 Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand

2 Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand

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Citation and License

Nanoscale Research Letters 2012, 7:57  doi:10.1186/1556-276X-7-57

Published: 5 January 2012

Abstract

Lead-free bismuth sodium titanate zirconate (Bi0.5Na0.5Ti1-xZrxO3 where x = 0.20, 0.35, 0.40, 0.45, 0.60, and 0.80 mole fraction) [BNTZ] ceramics were successfully prepared using the conventional mixed-oxide method. The samples were sintered for 2 h at temperatures lower than 1,000°C. The density of the BNTZ samples was at least 95% of the theoretical values. The scanning electron microscopy micrographs showed that small grains were embedded between large grains, causing a relatively wide grain size distribution. The density and grain size increased with increasing Zr concentration. A peak shift in X-ray diffraction patterns as well as the disappearance of several hkl reflections indicated some significant crystal-structure changes in these materials. Preliminary crystal-structure analysis indicated the existence of phase transition from a rhombohedral to an orthorhombic structure. The dielectric and ferroelectric properties were also found to correlate well with the observed phase transition.

Keywords:
ceramics; X-ray diffraction; dielectric properties; ferroelectricity