Ceramics-Silikáty 52, (1) 45 - 48 (2008) |
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MICROSTRUCTURE AND DIELECTRIC PROPERTIES OF BaTiO₃–Nb₂O₅–Zn0.8Mg0.2TiO₃ TERNARY SYSTEM |
Tang Bin, Zhang Shuren, Zhou Yiaohua,
Xiang Longcheng |
State Key Laboratory of Electronic Thin Films and Integrated Devices,
University of Electronic Science and Technology of China, Chengdu 610054, China
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Keywords: Barium titanate, Dielectric properties, X8R, Curie temperature, ZMT, Niobium |
Ceramics of BaTiO₃–Nb₂O₅–Zn0.8Mg0.2TiO₃(ZMT) composition were prepared by solid state reaction. The influence of Nb₂O₅
and ZMT addition on phase transition, microstructure, temperature-capacitance change (TCC), temperature dependence of
permittivity and Curie temperature (Tc) have been studied profoundly. With only 1 mol% Nb doping, a single perovskite phase
has been observed. Nevertheless, when Nb amount exceeded 2 mol%, a secondary phase of BaTiNb₄O₁₃ was observed. The
SEM and XRD analysis showed that the solubility of ZMT in BaTiO₃ with 1 mol% Nb is < 4 mol%. It was observed that for
a fixed amount of ZMT dopant increasing the amount of Nb content decreased the room temperature dielectric constant and
shifted the Tc to higher temperatures. Finally, a new dielectric sintered in air atmosphere at intermediate temperature
(1180°C) was obtained with large permittivity, low dissipation factor and high resistivity, meeting EIA X8R specification. |
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