11.Sr4RTiNb9O30陶瓷的制备及其介电特性*

胡长征、朱其华

（桂林理工大学，广西有色金属及特色材料加工省部共建国家重点实验室培育基地，有色金属及材料加工新技术教育部重点实验室，有色金属氧化物电功能材料与器件广西高校重点实验室，材料科学与工程学院，广西桂林，541004）

关键词：钨青铜结构；介电性能；铁电体

中图分类号：TB303 文献标识码：A

摘要：通过固相反应法合成制备了Sr₄RTiNb₉O₃₀(R= Sm、Eu、Gd)陶瓷，并通过X射线衍射仪、扫描电子显微镜、精密阻抗分析仪以及铁电性能测试系统对其进行了物相、结构和介电特性分析. 结果表明：Sr₄RTiNb₉O₃₀(R=Eu、Gd)陶瓷为P4bm四方钨青铜结构，而Sr₄SmTiNb₉O₃₀为pnma正交结构. 陶瓷表面晶粒均匀、致密且孔隙度低；从常温至300℃，三种陶瓷的介电常数和损耗均保持平稳，其中1MHz下，介电常数变化率为±5％；当温度升至500℃时，三种陶瓷均出现了介电异常增大现象；三种陶瓷在室温下均具有微弱的铁电性.

Preparation and Dielectric properties of Sr₄RTiNb₉O₃₀ ceramics

HU Chang-zheng, ZHU Qi-hua

（Guangxi Ministry-Province Jointly-Constructed Cultivation Base forState Key Laboratory of Processing for Non-ferrous Metal and FeaturedMaterials, Key Laboratory of New Processing Technology for Nonferrous Metalsand Materials, Ministry of Education,Guangxi Universities Key Laboratory ofNon-ferrous Metal Oxide Electronic Functional Materials and Devices,

College of Material Science and Engineering，Guilin University of Technology, Guilin 541004, China）

Key words：Tungsten bronze structure; Dielectric constant; Ferroelectric

Abstract：Sr₄RTiNb₉O₃₀(R=Sm, Eu, Gd) ceramics weresynthesized and prepared by solid state reaction. The phase，structure and dielectric properties of these three ceramics werestudied by X-ray diffraction, scanning electron microscope, precision impedanceanalyzer and ferroelectric testing system. The results indicated that Sr₄RTiNb₉O₃₀(R= Eu, Gd)ceramics have tetragonal tungsten bronze structure with spacegroup P4bm while Sr₄SmTiNb₉O₃₀has anorthorhombic pnma structure.The grain growth on the surface of these ceramic are compact and uniform，and the porosity are very low. The dielectric constant and loss ofthe three ceramics keep stable during the temperature range from roomtemperature to 300 ℃ with anespecially permittivity change about ±5％ at 1 MHz. All the three ceramics have dielectric abnormality when the temperature increase to500 ℃,while having weakferroelectricity at room temperature．