细晶粒BaTiO3陶瓷的微结构及介电性能测试

采用放电等离子烧结技术，在９００℃下得到细晶粒尺寸的、均匀的、纯ＢａＴｉＯ３陶瓷。对样品的高分辨电镜分析表明，晶粒中只有１８０°电畴，没有９０°电畴，晶界宽度相当于两倍的晶格常数．同时观察到有部分孪晶出现．对细晶粒陶瓷介电性能的测量表明，介电常数对晶粒尺寸有明显的依赖关系，认为李晶的存在是导致小晶粒陶瓷介电常数没有迅速降低的原因之一．对这一效应，用通常的串、并联模型不能很好地拟合。

Dielectric Properties and Microstructure of Fine-grained BaTiO3 Ceramics

Fine-grained pure BaTiO3 ceramics with homogeneous microstructures were obtained at 900℃ by means of a new sintering method-Spark Plasma Sintering (SPS). The result of HRTEM analysis shows that there areonly 180°domains exiting in the grains and the thickness of grain boundary is approximately two times of the crystal lattice constant. Meanwhile some twin grains can be found in the micrographs, and an obvious dependence of dielectric constant on grain sizes obtained on the basis of measuring the dielectric properties of the fine-grained ceramics. The existence of twins is one of the reasons that result in the dielectric constant of the fine-grained ceramics decreasing not sharply. This effect cannot be accurately fitted by the common seriesparallel model.