超细BaTiO_3陶瓷晶粒尺寸对介电性能的影响

GRAIN SIZE EFFECT ON DIELECTRIC PROPERTIES OF ULTRAFINE BaTiO 3 CERAMICS

通过对粒径均匀分布的细晶粒纯ＢａＴｉＯ３陶瓷介电性能研究发现，陶瓷的介电常数和介电损耗随晶粒粒度发生明显变化．随晶粒的减小，相变弥散，Ｃｕｒｉｅ温度降低，介电常数和介电损耗减小．平均晶粒度２８０ｎｍ的样品具有高的室温介电常数，部分晶粒仍保持铁电相结构是导致高介电常数的原因．

The effect of grain size on the dielectric properties of high_purity stoichiometric BaTiO 3 was investigated. It is found that the dielectric constant and dissipation factor are remarkably influenced by the grain size of BaTiO 3. With the decrease of grain size, the dielectric constant, dissipation factor and Curie point decrease, and the phase transition becomes dispersed. The specimen with grain size of 280 nm has a high ε r at room temperature, which can not be explained by the earlier theories. Some of the grains still remain tetragonal phase, that is ascribed to the high value of relative dielectric constant.