Influence of glass compositions on the microstructure and dielectric properties of low temperature fired BaTi_4O_9 microwave material with copper electrodes in reducing atmosphere

摘要

BaTi_4O_9 (BT4) dielectric ceramics, containing 10 wt% BaO-ZnO-B_2O_3-SiO_2 (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 SiO_2 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 BaCuO_2 phase, when the BZBS glass composition with lower content of SiO_2 (less than 20 wt%), and transformation of some BaTi_4O_9 into barium titanate with various ratios of Ba/Ti, which, fortunately, does not seriously degrade the dielectric properties.