二次烧成冷却条件对SrTiO_3基晶界层电容器晶界结构及性能的影响

以化学计量配比的SrTiO_3为基,采用PbO-Bi_2O_3-B_2O_3-CuO系氧化物为绝缘涂层,研究了二次烧成冷却条件对晶界层电容器晶界结构及性能的影响。实验结果表明,淬火有利于制备高表观介电常数的晶界层电容器。对炉冷和淬火样品的SEM/EDAX分析表明,淬火样品晶界以扩散层为主,第二相主要集中在三角晶界处,同时淬火样品晶界第二相成份比炉冷样品的要均匀,没有发生相分离。淬火样品晶界较少及均匀第二相的存在,是造成淬火样品性能比炉冷样品要好的原因。炉冷样品晶界第二相发生了相分离,第二相中有富Cu相和富Ti相析出。

EFFECT OF COOLING CONDITIONS OF SECOND FIRING ON GRAIN BOUNDARY MICROSTRUCTURE AND DIELECTRIC PROPERTIES OF SrTiO_3-BASED GBLC

The effects of cooling conditions of the second firing on the dielectric properties and the grain boundary microstructure of SrTiO_3-based GBLC have been investigated. Measurement of the dielectric properties in- dicates that the air-quenched GBLC shows much higher appearent permittivity and lower dielectric loss than the furnace-cooled GBLC. The grain boundary microstructures of these two kinds of GBLC have been stu- died by SEM/EDAX. In air-quenched samples, a more small amount and a more equal composition of grain boudary second phase which exists triangle grain boundary principally have been observed, and the phase disengagement in the grain boundary second phase has not been observed.