（Ba0.2Sr0.8）1-1.5xBixZn0.04T i0.98O3陶瓷结构及介电性能的研究

采用传统固相反应方法，制备了（Ba0.2Sr0.8）1-1.5xBixZn0.04Ti0.98O3（x=0.00、0.01、0.02、0.03）陶瓷材料，用X射线衍射、扫描电子显微镜和变温介电谱方法，对它们的晶格结构、微观形貌和复介电常数进行了测量和分析.结果表明：1）Zn2＋和Bi3＋进入到Ba0.2Sr0.8TiO3晶格中并与之形成ABO3钙钛矿型固溶体；2）随Bi2O3掺入，陶瓷的室温晶系结构由立方相转变为四方相，同时出现在约120K的弥散相变转化为弛豫相变；3）Bi2O3掺杂对晶粒生长有明显的抑制作用，但晶粒之间的连接性增强，陶瓷的致密度增加；4）当T=300K，f=1Hz，当Bi3＋的掺杂量为0.01mol时，陶瓷样品室温介电常最大（ε＇=1529.95），此时室温介电损耗值为最大（tanδ=3.366×10-2）.上述结果为该类陶瓷掺杂改性研究，以及弛豫相变机制探索提供参考.

Study on the Structure and Dielectric Properties of （Ba0.2Sr0.8）1-1.5xBixZn0.04Ti0.98O3 Ceramics

A series of （Ba0.2Sr0.8）1-1.5xBixZn0.04Ti0.98O3（x=0.00、0.01、0.02、0.03）ceramics were prepared by conventional solid state reaction method. The crystal structure, surface morphology and complex dielectric constant of the ceramics were measured and analyzed by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and dielectric spectroscopy. The results show that：1） Zn2＋and Bi3＋were co-doped into the Ba0.2Sr0.8TiO3 crystal lattice, and they form solid solution of ABO3 perovskite;2） with Bi2O3 doping, the crystal structures of the ceramic samples change from the cubic to tetragonal, and the diffuse phase transition near ~120K changes to the relaxation phase transition; 3） Bi 2 O 3 doping significantly inhibits the growth of grains, but enhances the connection between the grains and consequently leads to the increase of the ceramic density;4） When T=300K, f=1Hz, and the doping amount of Bi3＋ is 0.01mol, the room temperature dielectric constant of the ceramic sample has a maximum value （ε＇=1529.95）, and the room temperature dielectric loss is maximum （tanδ=3.366×10-2）. The above results undoubtedly have a certain reference value to the doping modifications of this ceramic class, as well as to the studies of the relaxation phase transition mechanism.