Low-temperature firing and microwave dielectric properties of ZnO–Nb2O5–TiO2–SnO2 ceramics with CuO–V2O5

The effects of CuO–V2O5 addition on the sintering temperature and microwave dielectric properties of ZnO–Nb2O5–TiO2–SnO2 were investigated. The CuO–V2O5 addition lowered the sintering temperature of ZnO–Nb2O5–TiO2–SnO2 ceramics effectively from 1150 to 860 °C due to the liquid-phase effect of Cu2V2O7 and Cu3(VO4)2, as observed by XRD. The microwave dielectric properties were found to strongly correlate with the sintering temperature and the amount of CuO–V2O5 addition. The maximum Qf values decreased with increasing CuO–V2O5 content, due to the formation of the second phase, Cu3(VO4)2 and CuNbO3. Zero τf value can be obtained by properly adjusting the sintering temperature. At 860 °C, ZnO–Nb2O5–TiO2–SnO2 ceramics with 1.5 wt.% CuO–V2O5 gave excellent microwave dielectric properties: ɛr = 42.3, Qf = 9000 GHz and τf = 8 ppm/°C.