Papers by Author: Hai Jun Niu

Abstract: In this research, SrBi2+xTa2O9 (SBT) powders with different Bi content were prepared using conventional solid-state reaction method. The SrBi2+xTa2O9 ceramics (x=0 ,0.2 ,0.4 ,0.6) were fabricated by the cold isostatic compaction and sintering in the air. Microstructure and dielectric, ferroelectric properties of SBT ceramics were investigated by XRD, SEM, EDAX and dielectric tester. The effects of Bi content on dielectric, ferroelectrc properties in SBT ceramics were discussed.

Abstract: SrBi2(Ta1-xNbx)2O9(SBTN) ferroelectric ceramics with typical bismuth layered perovskite structure were synthesized with a reactive hot-press sintering process at 1000°C for 2h. The as-sintered SBTN (x=0.2, 0.4, 0.6, 0.8) materials had a maximum relative density of 95.97%. Bi-layered perovskite structure was obtained. The grain sizes increased with increasing Nb content. In 1MHz frequency, remanent polarization (Pr) of SBTN (x=0.2, 0.4, 0.6, 0.8) were 10.0, 3.0, 1.7 and 1.0, while coercive field (Ec) of SBTN (x=0.2, 0.4, 0.6, 0.8) were 50, 32, 33 and 33kV/cm, respectively.