Preparation and modification of high Curie point BaTiO3-based X9R ceramics

BaTiO₃ (BT) based X9R ceramics with high permittivity about 1700 were prepared by doping and pre-sintering technique. Pure Bi_0.5Na_0.5TiO₃ (BNT) dopant was synthesized by the conventional solid state reaction first. Using this new approach, high performance BTBNT (BT doped with BNT) materials, owning high Curie temperature (139 °C), flat ferroelectric transition region and large permittivity at room temperature, were obtained. The effects of several dopants on dielectric properties of BTBNT ceramics were measured by the LCR meter. The suppression effect for the peaks in the dielectric constant at Curie temperature of these dopants have been ranked as follows: BiNbO₄ > CaZrO₃ > Nb₂O₅ > BNT.