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 ℃ to 950 ℃ 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 ℃ for 2 h presents good microwave dielectric properties of ε_r=19.0, high Q× f of 33802 GHz and low τ_f of 2.5 ppm/℃.