Effect of bismuth addition on sintering behavior and microwave dielectric properties of zinc titanate ceramics

The influences of Bi2O3 addition on the sintering behavior and microwave dielectric properties of ZnO-TiO2 ceramics were investigated. ZnO-TiO2 ceramics were prepared with conventional solid-state method and sintered at temperatures from 950°C to 1,100°C. The sintering temperature of ZnO-TiO2 ceramics with Bi2O3 addition could be effectively reduced to 1,000°C due to the liquidphase effects resulting from the additives. A proper amount of Bi2O3 addition could effectively improve the densification and dielectric properties of ZnO-TiO2 ceramics. The temperature coefficient of resonant frequency could be controlled by varying the sintering temperature and lead to a zero τf value. At 1,000°C, 1ZnO-1TiO2 ceramics with 1 wt.% addition gave better microwave dielectric properties ɛr of 29.3, a Q × f value of 22,000 GHz at 8.36 GHz, and a τf value of +17.4 ppm/ °C.