Liquid phase effect of Bi2O3 additive on densification, microstructure and microwave dielectric properties of Mg2TiO4 ceramics

Bi2O3 added Mg2TiO4 (MTO) ceramics were prepared by conventional solid-state reaction method. The effect of Bi2O3 on the densification, microstructure and microwave dielectric properties of MTO ceramics was investigated. The Bi2O3 addition significantly lowered the densification temperature of MTO ceramics from 1450°C to 1250°C, which is attributed to the liquid phase effect and smaller initial particle sizes. The dielectric constant (ϵr) was not significantly changed; while the Q × fo was tremendously influenced with Bi2O3 content. A fine combination of microwave dielectric properties (Q × fo = 160,500 GHz, (at 10.48 GHz) and ϵr = 13.2) were obtained for the 1 wt.% Bi2O3 added MTO sample, sintered at 1250°C. Further, the microwave dielectric properties of the MTO ceramics showed significant dependent on relative density, average grain size and oxygen vacancies.