SAG法Ba_（1－x）Sr_xTiO_3的介电性质

DIELECTRIC PROPERTIES OF Ba_(1-_x)Sr_xTiO_3 PREPARED BY SAG METHOD

ＸＲＤ法分析和介电测量结果表明，ＳＡＧ法Ｂａ１－ｘＳｒｘＴｉＯ３（ｘ＝０、０．３、０．５和０．７）微粉和陶瓷的室温结构为立方相．其居里温度明显低于相应Ｂａ１－ｘＳｒｘＴｉＯ３晶体或常规工艺陶瓷的值，但居里温度仍随着Ｓｒ２＋含量的增加而线性下降．晶粒含杂质Ｆｅ３＋以及表面富钡可能使其晶格立方化，从而使居里温度下降以及三方－正交和正交－四方铁电相变消失．

Ba1-xSrxTiO3 (x = 0, 0. 3, 0. 5 and 0. 7)were synthesized by the SAG method. The XRD analysis showed that they had a cubic structure at room temperature. The Curie temperature was measured by the temperature dependence of dielectric permittivity. Although it decreases linearly with increasing Sr content, it is obviously lower than the corresponding ceramics made by conventional method. The lowering of Curie temperature and disappearance of the trigonal-orthorhombic and orthorhombic-tetragonal phase transition might be caused by the impurity Fe3+ and the excess of Ba at the grain surface.