Effects of Rare-Earth La_2O_3 Addition on Microstructures and Electrical Properties of SrTiO_3 Varistor-Capacitor Dual Functional Ceramics  

作　　者：季惠明 李翠霞 孟辉 甘国友 严继康 

机构地区：[1]School of Materials, Tianjin University, Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin 300072, China [2]School of Materials and Metallurgical Engineering, Kunming University of Science and Technology, Kunming 650093, China

出　　处：《Journal of Rare Earths》2005年第1期55-58,共4页稀土学报（英文版）

基　　金：Project supported by Science and Technology Foundation of Yunnan Province (2002GG-09)

摘　　要：The effects of rare-earth La_2O_3 addition on microstructures and electrical properties of SrTiO_3 ceramics were investigated. Semiconductor SrTiO_3-based voltage-sensing and dielectric dual functional ceramics was prepared by a single step sintering technology in this study, and the effects of the content of La_2O_3 on characteristics of the product were discussed in terms of microstructures and electrical properties of materials. The results show that SrTiO_3-based ceramics doped with La_2O_3 exhibits more homogeneous grain distribution, greater grain size, and excellent voltage sensing and dielectric characteristics than those without La_2O_3 doping. The samples doped with 1 1% La_2O_3 were sintered at 1420 ℃ in N_2+C weak reducing atmosphere. The average grain size of the samples doped with La_2O_3 is 40 μm, the breakdown voltage of 19.7 V·mm^(-1), the nonlinear exponent of 7.2, and dielectric constant of 22500. The results reveal that final products are suitable to use in low operating voltage.The effects of rare-earth La_2O_3 addition on microstructures and electrical properties of SrTiO_3 ceramics were investigated. Semiconductor SrTiO_3-based voltage-sensing and dielectric dual functional ceramics was prepared by a single step sintering technology in this study, and the effects of the content of La_2O_3 on characteristics of the product were discussed in terms of microstructures and electrical properties of materials. The results show that SrTiO_3-based ceramics doped with La_2O_3 exhibits more homogeneous grain distribution, greater grain size, and excellent voltage sensing and dielectric characteristics than those without La_2O_3 doping. The samples doped with 1 1% La_2O_3 were sintered at 1420 ℃ in N_2+C weak reducing atmosphere. The average grain size of the samples doped with La_2O_3 is 40 μm, the breakdown voltage of 19.7 V·mm^(-1), the nonlinear exponent of 7.2, and dielectric constant of 22500. The results reveal that final products are suitable to use in low operating voltage.

关 键 词：inorganic nonmetallic materials SrTiO_3 VARISTOR La_2O_3 microstructure electrical property rare earths 

分 类 号：TQ174[化学工程—陶瓷工业]