Structure and dielectric properties of (1-x)Bi0.5Na0.5TiO3-xBaTiO3 piezoceramics prepared using hydrothermally synthesized powders

The influence of different processing parameters and various Ba2+ addition (up to 10 mol%) on the structure and dielectric properties of Bi0.5Na0.5TiO3-BaTiO3 (BNT-BT) ceramics was investigated. The powders were hydrothermally synthesized in alkaline environment at 180 °C for different time periods. X-ray diffraction confirmed the presence of dominant rhombohedral Bi0.5Na0.5TiO3 phase and a small amount of secondary pyrochlore Bi2Ti2O7 phase in the pure BNT powders. In addition, one-dimensional Na2Ti2O7 structure was also observed in the powder hydrothermally treated for a long time (i.e. 48 h). The amount of secondary pyrochlore phase in the BNT-BT powders increases with the increase of Ba2+ content. The synthesized powders were pressed into pellets and finally sintered at various temperatures up to 1150 °C. High density (more than 90 %TD) was obtained in all BNT-BT sintered samples. Optimal sintering parameters were chosen in order to obtain dense ceramics with the optimal phase compo...

本研究探究了不同工艺参数及不同Ba²+掺杂量（最高可达10 mol%）对Bi₀.₅Na₀.₅TiO₃-BaTiO₃（BNT-BT）陶瓷的结构与介电性能的影响。粉体通过水热法在碱性环境、180℃条件下合成，反应时长各不相同。X射线衍射（X-ray diffraction）表征证实，纯BNT粉体中以菱方相Bi₀.₅Na₀.₅TiO₃为主相，同时伴随少量次生焦绿石相Bi₂Ti₂O₇。此外，对水热反应时长较长（即48小时）的粉体进行分析时，还观察到一维Na₂Ti₂O₇结构。BNT-BT粉体中的次生焦绿石相含量随Ba²+掺杂量的提升而增加。将合成得到的粉体压制成坯体，随后在最高可达1150℃的不同温度下进行烧结。所有烧结后的BNT-BT样品均获得了高于90%理论密度（TD）的致密度。为获得物相组成最优的致密陶瓷，本研究选取了最优烧结参数……