Effect of CaO/SnO2 additives on the microstructure and microwave dielectric properties of SrTiO3-LaAlO3 ceramics

摘要

The effect of CaO/SnO2 additives on the sintered properties, phase composition, microstructures, and dielectric properties of 0.6SrTiO(3)-0.4LaAlO(3) (6ST-4LA) microwave dielectric ceramics prepared by conventional solid-state reaction method were investigated. The results showed that CaO/SnO2 as additives had no obvious influence on phase composition of 6ST-4LA ceramics, and all of the samples exhibited pure ABO(3) perovskite structures. Adding a moderate amount of CaO/SnO2 not only effectively lowered the sintering temperature from 1550 degrees C to 1400 degrees C, but also improved the dielectric properties, due to formation of the perovsldte solid solution, and decreased the microstructure defects and intrinsic loss. The 0.25 wt% CaO-doped 6ST-4LA ceramics with 0.50 wt% SnO2, sintered at 1400 degrees C for 3 h had the optimal integrated microwave dielectric properties: epsilon(r)=44.87, Q.f=65277 GHz(at 6.5 GHz), tau(f)=-1.56x10(-6)/degrees C.