Structure and dielectric properties of ZnO and Nb2O5 doped BaO-TiO2 system microwave ceramics

The microwave dielectric properties and microstructure of BaTi4.3ZnyO9.6+y +0.02 mol% SnO2+0.01 mol% MnCO3+x mol% Nb2O5(x=0–0.05, y=0–0.08) system ceramics were studied as a function of the amount of ZnO and Nb2O5 doped. Addition of (y=0–0.05) ZnO and (x=0–0.025) Nb2O5 enhanced the reactivity and decreased the sintering temperature effectively. It also increased the dielectric constant ɛr and quality factor Q(=1/tan δ) of the system due to the substitution of Ti4+ ions with incorporating Zn2+ and Nb5+ ions, which was analyzed by the reaction ZnO+Nb2O5+ 3 TiTix → ZnTi+ 2NbTi·+3TiO2. When the system doped with (y=0.05) ZnO and (x=0.025) Nb2O5 were sintered at 1 160 °C for 6 h, the ɛr, Qf0 value and τf were 36.5, 42 000 GHz, and+1.8 ppm/°C, respectively, at 5 GHz.