室温固态反应制备纳米Ba1－xSrxTiO3固溶体及其结构与介电性能研究

采用室温固态反应合成了一系列Ba_1－xSr_xTiO₃固溶体纳米粉末(0≤x≤1.0). 经XRD物相分析和d-间距-组成图证明, 产品为立方晶系的完全互溶取代固溶体. TEM形貌观察, 粒子基本为球形, 平均粒径40 nm. 该方法具有产率高, 无需溶剂, 对环境无污染等优点. 通过制陶实验, 分别测定了该系列固溶体的室温介电常数、介电损失以及介电常数随温度的变化. 结果发现, 采用室温固态反应在BaTiO₃中掺入适量锶, 由于掺杂离子均匀进入母体晶格, 引起居里点降低, 室温介电常数达11000以上, 介电损耗由BaTiO₃纯相的0.03 (3%)降为0.008 (0.8%). 纳米粉体的烧结温度为1180 ℃, 比传统微米级粉体的烧结温度降低100～150 ℃.

Structure and Dielectric Property of Nano-Ba1-xSrxTiO3 Solid Solutions Synthesized by Solid-state Reaction at Room Temperature

A series of nano-Ba_1－xSr_xTiO₃ (0≤x≤1.0) solid solutions were synthesized by solid-state reaction at room temperature. XRD and d-spacing-component figures of the solid solution powder demonstrated that the compounds were mutually miscible in the solid solutions, and TEM showed that they were uniform and substantially spherical particles with an average size of 40 nm in diameter. The remarkable advantages of the method are high yields, solvent-free, and environmental benign. The results of preparing ceramics showed that after adulterating with Sr^2＋ in pure BaTiO₃ phase, the dielectric constant obviously increased and dielectric loss reduced at normal temperature. Furthermore, we also discussed the micro-structure of the BaTiO₃ ceramics at different sintering temperatures, then found that the sintering temperature was nearly 100～150 ℃ lower than that of the traditional micro-powder.