Dresden 2011 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 12: Poster

DF 12.4: Poster

Mittwoch, 16. März 2011, 15:00–17:30, P1

Preparation of nano-crystalline BaTiO₃ powder in a sol-precipitaion process — •Yanling Gao, Vladimir Shvartsman, and Doru C. Lupascu — Institut für Materialwissenschaft, Universität Duisburg-Essen, Essen, Germany

We are trying to synthesize uniform-sized nanoparticles having a high dielectric permittivity to be used in conjunction with conducting polymer in order to alter the electric properties of the latter. For this purpose, the synthesis of hydrophobic nano-crystalline BaTiO₃ is investigated. Cubic and hydrophobic BaTiO₃ nanopowders with a size below 20 nm were directly synthesized by sol-precipitaion under alkaline conditions at 100^∘C using the water - insoluble titanium (IV) isopropoxide oleate (Ti(OR)_4−x(RCOO)_x) precursor. The latter prepared by reacting titanium (IV) isopropoxide with oleic acid. The crystallinity and phase purity of the nanopowders were studied with X-ray diffraction spectrometry (XRD). The size and the microstructure of the BaTiO₃ nanopowder were analysed by Scanning Electron Microscopy (SEM). The XRD pattern of as-precipitated nanopowders showed weak and broad reflections characteristic of crystalline BaTiO₃ with evidence of the presence of BaCO₃. The as-prepared nanopowders were calcined at 500^∘C/6hrs in air to obtain perovskite of BaTiO₃ phase. The obtained BaTiO₃ were further pressed into pellets and sintered at 950^∘C/4hrs in air to get dense ceramics. Dielectric properties of these ceramics are measured as a function of temperature.