The effect of phosphor doping on the sintering behaviour, microstructure and dielectric properties of BaTiO3 has been investigated. Diisopropyl phosphinate is added to high-purity BaTiO3 powder prepared by the wet chemical method with a final amount of 0.14 wt. P2O5 with respect to the BaTiO3. Phosphor-doped BaTiO3 ceramics with a high density and uniform grain size have been produced by using wet processing and pressureless sintering without any binder. A scanning electron microscope, thermometric analysis, X-ray diffraction and an impedance analyser have been used to determine the microstructure as well as the dielectric properties. The phosphor cations can form a liquid phase belonging to the ternary system BaO-TiO2-P2O5, leading to the formation of BaTiO3 ceramics with high density at low temperature. Phosphor-doped BaTiO3 ceramics with a high density of 96 D-th are obtained by sintering at 1200 degrees C with a soaking time of 2 h. The dielectric constants of samples sintered at 1150 and 1200 degrees C are as high as 6100 and 5500, respectively; the Curie temperature of samples decreases with decreasing sintering temperature, Doping with a small amount of phosphor can improve the sintering and dielectric properties of BaTiO3 ceramics. (C) 1998 Elsevier Science S.A. All rights reserved. References: 10
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