Structural and electrical properties of microwave -processed BaTiO3 ceramics

Abstract

Barium titanate (BaTiO3) was synthesized and sintered by microwave processing at 2.45 GHz. Appropriate amounts of BaCO3 and TiO2 were used as starting materials for the synthesis. BaTiO3 phase was obtained by heating the precursors in a multimode microwave cavity at 1450oC for just 25 minutes. The synthesis and sintering were carried out in air. A relative density of 97% was obtained. By contrast, it was found that to achieve the same densification, it required 4 hours of soaking at 1450oC in a conventional sintering process. The dielectric properties show the abrupt discontinuities in dielectric constant vs. temperature plots; typical properties of first order transitions. Above the Curie temperature the dielectric constant follows Curie-Weiss law with Curie constant C=1.3-1.4´105 oC.