BaTiO_3烧结陶瓷的微结构及介电性能研究

Study on Microstructure and Dielectric Properties of BaTiO_3 Ceramics

以超重力反应沉淀法制得的纳米BaTiO3为初始粉体,在不同温度烧结得到BaTiO3陶瓷。分别用SEM和阻抗分析仪测试陶瓷微结构和介电性能。结果表明:陶瓷微结构尤其晶粒尺寸对陶瓷介电性能影响极大;烧结温度低于1250°C时得到细晶粒陶瓷(d=300～400nm),表现出明显的低介电常数和相变弥散的特征;烧结温度达1250°C时得到陶瓷超出细晶粒陶瓷范围,烧结温度为1300°C时,得到陶瓷晶粒尺寸为3～4μm,室温介电性能优于粗晶粒陶瓷。

BaTiO_3 ceramics sintered at different temperature is prepared from powders synthesized by high gravity reactive precipitation (HGRP). The microstructure and dielectric properties are studied by SEM and impedance analyzer. The results show that: the microstructure of ceramics especially the grain size has great effect on dielectric properties; fine grain ceramics (d=300～400 nm) obtained when sintered temperature is lower than (1 250 °C,)which exhibits the characteristics of low dielectric constant and phase transition diffusion; ceramics obtained when sintered temperature is up to or higher than (1 250 °C) is out of the range of fine grain ceramics. When sintered temperature is 1 300 °C ceramics with grain size of 3～4 μm is prepared and the ambient dielectric properties are better than that of coarse grain ceramics.