Constitutional Design and Dielectric Properties of BST Graded Ceramics
来源期刊：材料热处理学报2004年第5期
论文作者：JEON Jae-ho WU Shu-yan CHENG Hua-rong ZHU Jing-chuan
关键词：barium strontium titanate; boric oxide; Curie point; axial ratio; graded material;
摘 要：The effect of B2O3 dopant and SrTiO3 (ST) content on lattice parameters and ferro-paraelectric phase transition temperature (i.e. Curie point) of Ba1-xSrxTiO3 (BST, x=0～0.4) ceramics was investigated, and then BST graded ceramics with controllable transition temperature zone were fabricated and characterized for their dielectric properties. The results show that with the increase of ST content, c/a ratio and Curie point of both doped and undoped ceramics decreased linearly but with different rate of change, resulting from different ionic radiuses of Ba2+, Sr2+ and B3+. Moreover, both c/a ratio and Curie point of doped BST increased slightly in comparison with that of undoped ones while the Curie point changed scarcely with dopant amount rising, which perhaps means that for BST grains with different ST content, B2O3 solubility was different but limited and most of boron (B) did not incorporate into BST grains. Through controlling composition,transition temperature of graded ceramics can be designed. For doped graded ceramics sintered at 1250℃, its dielectric properties was much better than that of undoped one sintered at 1400℃, and Curie peak of both samples was broadened effectively via graded structure.
JEON Jae-ho1，WU Shu-yan2，CHENG Hua-rong3，ZHU Jing-chuan3
(1.Korea Institute of Machinery and Materials, Changwon 641-010, Korea;
2.Jiamusi University, Jiamusi 154007, P.R. China;
3.Harbin Institute of Technology, Harbin 150001, P.R. China)
摘要:The effect of B2O3 dopant and SrTiO3 (ST) content on lattice parameters and ferro-paraelectric phase transition temperature (i.e. Curie point) of Ba1-xSrxTiO3 (BST, x=0～0.4) ceramics was investigated, and then BST graded ceramics with controllable transition temperature zone were fabricated and characterized for their dielectric properties. The results show that with the increase of ST content, c/a ratio and Curie point of both doped and undoped ceramics decreased linearly but with different rate of change, resulting from different ionic radiuses of Ba2+, Sr2+ and B3+. Moreover, both c/a ratio and Curie point of doped BST increased slightly in comparison with that of undoped ones while the Curie point changed scarcely with dopant amount rising, which perhaps means that for BST grains with different ST content, B2O3 solubility was different but limited and most of boron (B) did not incorporate into BST grains. Through controlling composition,transition temperature of graded ceramics can be designed. For doped graded ceramics sintered at 1250℃, its dielectric properties was much better than that of undoped one sintered at 1400℃, and Curie peak of both samples was broadened effectively via graded structure.
关键词:barium strontium titanate; boric oxide; Curie point; axial ratio; graded material;
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