Effects of BaCu(B2O5) addition on sintering temperature and microwave dielectric properties of Ba5Nb4O15–BaWO4 ceramics

The effects of BaCu(B2O5) (BCB) addition on the microstructure, phase formation, and microwave dielectric properties of Ba5Nb4O15−BaWO4 ceramic are investigated. As a sintering aid, BaCu(B2O5) ceramic could effectively lower the sintering temperature of Ba5Nb4O15−BaWO4 ceramic from 1100 °C to 950 °C due to the liquid-phase effect. Meanwhile, BaCu(B2O5) addition effectively improves the densification of Ba5Nb4O15−BaWO4 ceramic and significantly influences the microwave dielectric properties. X-ray diffraction analysis reveals that Ba5Nb4O15 and BaWO4 coexist with no crystal phase of BaCu(B2O5) in the sintered ceramics. The Ba5Nb4O15−BaWO4 ceramics with 1.0 wt% BaCu(B2O5) sintered at 950 °C for 2 h presents good microwave dielectric properties of er = 19.0, high Q×f of 33802 GHz and low τf of 2.5 ppm/°C.