BaO－Gd2O_3－TiO_2体系相关系、相结构与电性质的研究

PHASE RELATIONS, COMPOUNDS AND ELECTRICAL PROPERTIES IN THE SYSTEM BaO-Gd_2O_3-TiO_2

借助于固相合成、Ｘ射线衍射分析和交流阻抗法测定了ＢａＯ－Ｇｄ＿２Ｏ＿３－ＴｉＯ＿２体系的相关系、相结构与电性质。发现在研究的部分体系内有两个三元化合物新相：ＢａＧｄ２Ｔｉ＿４Ｏ＿（１２）属正交晶系，其晶胞参数为：ａ＝１．２１３７２ｎｍ，ｂ＝２．２３２６５ｎｍ，ｃ＝０．３８１９５ｎｍ，Ｖ＝１．０３４９７０ｎｍ￣３，Ｚ＝４；Ｂａ＿（１１）Ｇｄ＿４Ｔｉ＿７Ｏ＿（３１）属六方晶系，其晶胞参数为：ａ＝０．５９５４７ｎｍ，ｃ＝２．９７１９７ｎｍ，Ｖ＝０．９１２６３ｎｍ￣３，Ｚ＝１。在研究的部分体系内含有１３个单相区，２５个二相区，１３个三相区。测定了相关物相的电导和介电常数，发现ＢａＧｄ＿２Ｏ＿４与Ｇｄ＿２Ｔｉ＿２Ｏ＿７有很高的介电常数（ε’＞２００），是很有希望的功能材料。

Phase relations,compounds and their electrical properties in thesystem BaO-DGd_2O_3-TiO_2 were investigated by means of solid synthesis , x-ray diffraction analysis and a. c. impedance technique.Two new compounds:BaGd_2Ti_4O_(12) (with orthorhombic unit cell:a= 1.21372nm;b=2.23265nm; c=0.38195nm;V=1.034970nm￣3; Z=4) and Ba_(11)Gd_4Ti_7O_(31) (with hexagonal unit cell: a=0. 59547nm;c=2. 97197nm;V= 0. 91263nm￣3;Z= 1) ;13 single-phase- regions,25 two-phase-regions and 13 three-phase-regions were found in the investigated part of the system BaO-Gd_2O_3-TiO_2 (Gd_2O_3-TiO_2-rich). The conductivities and dielectric constants of the pure phase were also measured.It is found that BaGd_2O_4 and Gd_2Ti_2O_7 have relatively high dielectric constant (ε’>200).They could be promising functional materials.