Nb／Co比对钛酸钡锶电容器陶瓷性能的影响

Effect of Nb/Co Ratio on Properties of (Ba, Sr)TiO_3 Capacitor Ceramics

研究了Nb2O5／Co2O3摩尔比(简称Nb／Co比,下同)对(Ba,Sr)TiO3(Barium Strontium Titanate,BST)铁电电容器陶瓷介电性能的影响,得到不同Nb／Co比与BST陶瓷性能的关系。借助扫描电镜(SEM)研究Nb／Co比对BST陶瓷微观结构的影响,采用X射线衍射(XRD)分析了BST陶瓷物相组成,探讨了Nb／Co比对BST陶瓷性能影响的机理。结果表明:当Nb／Co比为1．1,可得到满足X7R特性、介电常数为2449、耐压为5 MV／m以上综合性能好的BST陶瓷。Nb／Co比增大对BST陶瓷性能的影响是通过阻止晶粒生长、致密化、(适当增加Nb／Co比能细晶化、过量增加Nb／Co比导致少量晶粒异常长大、)宽化介电常数温度曲线、改善介电常数温度特性、减少介电常数、形成杂相、形成“晶核-晶壳”结构等进行。通过研究获得高介高压高稳定电容器陶瓷。

The influence of Nb2O5/Co2O3 mol ratio （Nb/Co） on the properties of （Ba,Sr）TiO3 （BST） capacitor ceramics were investigated ,and the relationship between the Nb/Co ratio and the properties of BST were obtained .The influence of Nb/Co ratio on the microstructure of BST ceramics were studied by scanning electron microscope and X-ray diffraction. The mechanism on modifying the properties and microstructure of the BST ceramics by doping various Nb/Co ratios was investigated. Results show that the BST ceramics with the optimal properties can be obtained when the Nb/Co ratio is 1.1, including the X7R property, a dielectric constant of 2449 and a breakdown voltage of more than 5 MV/m. The properties and microstructure of the BST ceramics were affected by Increasing the Nb/Co ratio due to the stopping of grain growth, the fining grain, the densifying, t.＇.e widening the εr- θ（dielectric constant temperature） curve, the improvement of εr- θ property, the decrease of dielectric constant, the formation of other phase, and the formation of ＂Core-Shell＂ structure. As a result, the capacitor ceramics with high dielectric constant, high voltage and high stability were obtained.