Ba_(0.8)Sr_(0.2-x)Ca_xTiO_3陶瓷微观结构和介电性能的研究

Microstructure and Dielectric Properties of the Barium Strontium Calcium Titanate Ceramic

采用固相法制备钛酸锶钙钡Ba_(0.8)Sr_(0.2-x)Ca_xTiO_3(x=0,0.04,0.08,0.12,0.16,0.2,BSCT)粉末,用X射线分析仪(XRD)和扫描电镜(SEM)对BSCT粉末的物相和显微形貌进行分析。将制备的BSCT粉末在200 MPa下压制成直径为12mm的小圆片压坯,制备的压坯在1400℃烧结2 h得到BSCT陶瓷,用排水法、扫描电镜(SEM)和阻抗分析仪分别对BSCT陶瓷样品的密度、显微形貌和介电性能进行分析,研究不同Ca含量对BSCT陶瓷样品性能的影响。结果表明:BSCT粉末在室温下均为四方相,晶格常数、晶粒大小随着Ca含量的增加先减小后增加;BSCT陶瓷样品的居里温度与晶轴率c/a呈正相关,Ca的加入有助于样品的致密化、介电常数的增加和介电损耗的降低;BSCT陶瓷样品的介电常数随着频率的增加而减小,介电损耗随着频率的增加先减小后增加。

The Ba0.8Sr0.2-xCaXTiO3 （BSCT） powders were prepared by solid state reaction method. The BSCT powders＇ phase and microstructure were investigated by XRD and SEM respectively. The BSCT powders prepared by solid state reaelion were pressed into dicks of 12 mm diameter under a force of 200 MPa. Then the samples were sintered at 1400℃ for 2 h in the air. The BSCT ceramics＇ density, mierostrueture as well as dielectric properties were analysed by method of Drainage method, SEM and Impedance analyzer, we investigated the impact of the different components Ca on the BSCT ceramics＇ properties. The results show that the BSCT powders were tetragonal phase at room temperature, the lattiee parameters and the ceramics＇ grain sizes reduce firstly- and increase afterward with the increasing Ca contents. Doping Ca was eontributing to the densifieation, the dielectric constants enhancement and dielectric loss reduetion of the BSCT sample. The Curie temperature was proportionate to crystal axis rate c/a. With the increasing frequeney, the dielectric constant decreases and the dielectric loss reduce firstly and increase afterward.