Influence of glass compositions on the microstructure and dielectric properties of low temperature fired BaTi4O9 microwave material with copper electrodes in reducing atmosphere

BaTi4O9 (BT4) dielectric ceramics, containing 10 wt% BaO–ZnO–B2O3–SiO2 (BZBS) glass frit as sintering aid were co-fired with copper paste under reducing atmosphere at 950 °C and investigated on microstructures and dielectric properties. Experimental results show the microstructures and microwave dielectric properties of BT4–BZBS glass composite materials are strongly dependent on the Ba–Zn–B–Si ratio, especially for the content of SiO2 addition, in BZBS glass. XRD and EDS results indicate that Cu reacts with BZBS glass-added BT4 ceramics seriously to form complicated reaction products such as BaCuO2 phase, when the BZBS glass composition with lower content of SiO2 (less than 20 wt%), and transformation of some BaTi4O9 into barium titanate with various ratios of Ba/Ti, which, fortunately, does not seriously degrade the dielectric properties.