Sintering Behavior, Phase Composition and Microwave Dielectric Characteristics of Mg4Nb2O9 Ceramics Doped with ZnO-B2O3-SiO2 Glass

The Mg4Nb2O9 doped with x mol% ZnO-B2O3-SiO2 (ZBS, 0 <= x <= 0.20) ceramics were prepared by a solid-state reaction method for developing low-fired microwave dielectric ceramics. The sintering temperatures of Mg4Nb2O9 ceramics were successfully lowered to 1100 degrees C by doping ZBS. With increasing x, the dielectric constant (epsilon(r) ) increased from 12.3 to 13.0 and the quality factor (Q x f) decreased from 140,000 GHz to 42,580 GHz, respectively. The well microwave dielectric properties of e (r) = 12.9, Q x f = 56470 GHz, and tau(f) = -59.8 ppm/degrees C were obtained for Mg4Nb2O9-0.15 mol% ZBS ceramics.