Effects of LiF addition on microstructure and dielectric properties of CaCu3Ti4O12 ceramics

Ceramics International Volume: 42 Issue: 10 Pages: 12005-12009 Published: 2016

2 de agosto de 2016 CDMF Artigo 0

FEG-SEM-micrographs-of-CCTO-sintered — FEG-SEM micrographs of CCTO sintered at 1090 °C and CCTO with 0.5mol% LiF sintered at 1050 °C.

Writers: T.C. Porfirio and E.N.S. Muccillo

Keywords: A. Sintering; C. Dielectric properties; D. Perovskites; E. Capacitors

Abstract: The effects of small amounts of lithium fluoride sintering aid on the microstructure and dielectric properties of CaCu₃Ti₄O₁₂ (CCTO) ceramics were investigated. CCTO polycrystalline ceramics with 0.5 and 1.0 mol% LiF, and without additive were prepared by solid state synthesis. Good densification (>90% of the theoretical density) was obtained for all prepared materials. Specimens without the sintering aid and sintered at 1090 °C exhibit secondary phases as an outcome of the decomposition reaction. The mean grain size is controlled by the amount of LiF in specimens containing the additive. Impedance spectroscopy measurements on CaCu₃Ti₄O₁₂ ceramics evidence the electrically heterogeneous nature of this material consisting of semiconductor grains along with insulating grain boundaries. The activation energy for grain boundary conduction is lower for specimens prepared with the additive, and the electric permittivity reached 53,000 for 0.5 mol% LiF containing CCTO.

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