Effects of TiO2 phases on the structural and dielectric properties of sintered BaTiO3 + x% mol Fe2O3 ceramics

摘要

The objective of this paper is to study the influence of TiO2 phases on the structural and dielectric properties of the BaTiO3 ceramics containing different amounts of Fe2O3. The pure BaTiO3 ceramics was prepared by a solid state reaction between BaCO3 and both of TiO2 phases, anatase (A) and rutile (R), respectively. We prepared the mixtures by stoichiometric way, which were calcined at 1100 degrees C during 2hrs. The formations of perovskites structures ABO(3) were confirmed by X-rays diffraction analysis. While the ceramics mixture with (1-x) BaTiO3+ x % Fe2O3 (where x = 1, 2, 5 and 7 wt %) compositions were prepared by the wet milling. Afterwards, the different pellets were fabricated by uniaxial compression and sintered at different temperatures (1300, 1350 and 1400 degrees C). The obtained results show an increase in the tetragonality due to the doping by Fe3+, consequencely an increase in the relative permittivity of samples prepared from TiO2(R) with both of Fe2O3 addition and sintering temperature. On the other hand, for the samples prepared from TiO2 (A) the obtained results show a decrease in both relative density and tetragonality with both of Fe2O3 addition and sintering temperature, as a consequence we get a decrease in the relative permittivity compared with pure BTA.