Low-temperature firing and microwave dielectric properties of Ca[(Li0.33Nb0.67)0.9Ti0.1]O3−δ ceramics with LiF addition

Abstract

The effects of LiF addition on sinterability, microstructure and microwave dielectric properties of Ca[(Li0.33Nb0.67)0.9Ti0.1]O3−δ ceramics were investigated. The LiF addition lowered the sintering temperature of Ca[(Li0.33Nb0.67)0.9Ti0.1]O3−δ ceramics effectively from 1180 to 840 °C. It was found that the bulk density and dielectric constant (εr) greatly decreased, the quality factor (Q·f) gradually increased, the temperature coefficient of resonant frequency (τƒ) shifted to a negative value with the increase amount of LiF addition. The dielectric properties (εr,Q·f, τf) of Ca[(Li0.33Nb0.67)0.9Ti0.1]O3−δ ceramics with 10 wt.% LiF sintered at 900 °C were 24.8, 19,300 GHz (at 4.16 GHz), −15.6 ppm/°C respectively. And those were 21.3, 20,450 GHz (at 4.59 GHz), −18.0 ppm/°C respectively for the specimen with 20 wt.% LiF at 840 °C.