Effects of Rare-Earth La2O3 Addition on Microstructures and Electrical Properties of SrTiO3 Varistor-Capacitor Dual Functional Ceramics
来源期刊：JOURNAL OF RARE EARTHS2005年第1期
论文作者：Gan Guoyou Meng Hui Li Cuixia Yan Jikang JI Huiming
Key words：inorganic nonmetallic materials; SrTiO3; varistor; La2O3; microstructure; electrical property; rare earths;
Abstract: The effects of rare-earth La2O3 addition on microstructures and electrical properties of SrTiO3 ceramics were investigated. Semiconductor SrTiO3-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 La2O3 on characteristics of the product were discussed in terms of microstructures and electrical properties of materials. The results show that SrTiO3-based ceramics doped with La2O3 exhibits more homogeneous grain distribution, greater grain size, and excellent voltage sensing and dielectric characteristics than those without La2O3 doping. The samples doped with 1.1% La2O3 were sintered at 1420 ℃ in N2+C weak reducing atmosphere. The average grain size of the samples doped with La2O3 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.
Gan Guoyou1，Meng Hui2，Li Cuixia2，Yan Jikang1，JI Huiming2
(1.School of Materials and Metallurgical Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2.School of Materials, Tianjin University, Key Laboratory for Advanced Ceramics and Machining Technology of Ministry of Education, Tianjin 300072, China)
Abstract:The effects of rare-earth La2O3 addition on microstructures and electrical properties of SrTiO3 ceramics were investigated. Semiconductor SrTiO3-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 La2O3 on characteristics of the product were discussed in terms of microstructures and electrical properties of materials. The results show that SrTiO3-based ceramics doped with La2O3 exhibits more homogeneous grain distribution, greater grain size, and excellent voltage sensing and dielectric characteristics than those without La2O3 doping. The samples doped with 1.1% La2O3 were sintered at 1420 ℃ in N2+C weak reducing atmosphere. The average grain size of the samples doped with La2O3 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.
Key words:inorganic nonmetallic materials; SrTiO3; varistor; La2O3; microstructure; electrical property; rare earths;
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