Structural and electrical properties of microwave -processed BaTiO₃ ceramics

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 multi-mode microwave cavity at 1450°C 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 1450°C 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=1.3-1.4x10⁵°C.