Effects of Zirconia on Microstructure and Dielectric Properties of Barium Titanate Ceramics |
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Authors: | Timothy R. Armstrong Laurie E. Morgens Alena K. Maurice Relva C. Buchanan |
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Affiliation: | Department of Materials Science and Engineering, University of lllinois, Urbana, lllinois 61801 |
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Abstract: | Dielectric properties and structural characteristics of BaTiO3 ceramics are significantly influenced by small addition (2 wt%) of ZrO2. SEM and TEM observations revealed enhanced microstructural uniformity and retarded grain growth depending on sintering temperature. Above 1320°C, Zr diffusion into the BaTiO3 lattice resulted in a chemical modification of the tetragonal structure and the development of core–shell grains. Below 1320°C, TEM analysis showed ZrO2 at the grain boundaries as discrete particles (∼0.03μm). X-ray diffraction analysis revealed a decrease in the axial (c/a) ratio with decreasing grain size. A corresponding decrease in the spontaneous polarization, and twinned domain structures, were also observed in the fine-grained ceramics. These samples also showed a flattened permittivity response with temperature and significantly lower losses. |
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Keywords: | barium titanate dielectric properties zirconia processing grain boundaries |
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