Effect of Zn-excess on sintering behavior and microwave dielectric properties in Mg 0.97 Zn 0.03 TiO 3 ceramics

Abstract The microstructures and microwave dielectric properties of Zn-excess (0.0 mol%, 0.5 mol%, 1.0 mol%, 2.0 mol%, 3.0 mol%) Mg 0.97 Zn 0.03 TiO 3 ceramics prepared via the conventional solid-state reaction route were investigated. With Zn-excess doped, the sintering temperature of the specimens can be slightly reduced from 1275 °C to 1250 °C. Microwave dielectric properties of the compounds were studied systematically. A slight Zn-excess does not have obvious effect on the relative dielectric constant ( e r ) and temperature coefficient of resonant frequency ( τ f ) of the specimens. However, the Q × f is very sensitive to the amount of Zn-excess. As the content of Zn-excess increased, the MgTi 2 O 5 phase which was derived from sample without Zn-excess disappeared. Along with the augmentation of Zn-excess, the Q × f , bulk density and e r show an initial increase, followed by a decrease, but the last two factors do not change much. An extremely high Q × f of 277,500 GHz (at 8.5 GHz) together with an e r of 17.66 and a τ f of −55.09 × 10 −6 /°C can be found for Mg 0.97 Zn 0.03 TiO 3 specimen with 0.5 mol% Zn-excess sintered at 1250 °C for 4 h.