Effect of Zn-excess on sintering behavior and microwave dielectric properties in Mg0.97Zn0.03TiO3 ceramics

The microstructures and microwave dielectric properties of Zn-excess (0.0 mol%, 0.5 mol%, 1.0 mol%, 2.0 mol%, 3.0 mol%) Mg0.97Zn0.03TiO3 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 degrees C to 1250 degrees C. Microwave dielectric properties of the compounds were studied systematically. A slight Zn-excess does not have obvious effect on the relative dielectric constant (epsilon(r)) and temperature coefficient of resonant frequency (tau(f)) of the specimens. However, the Q x f is very sensitive to the amount of Zn-excess. As the content of Zn-excess increased, the MgTi2O5 phase which was derived from sample without Zn-excess disappeared. Along with the augmentation of Zn-excess, the Q x f, bulk density and epsilon(r) show an initial increase, followed by a decrease, but the last two factors do not change much. An extremely high Q x f of 277,500 GHz (at 8.5 GHz) together with an epsilon(r) of 17.66 and a tau(f) of -55.09 x 10(-6)/degrees C can be found for Mg0.97Zn0.03TiO3 specimen with 0.5 mol% Zn-excess sintered at 1250 degrees C for 4 h. (C) 2014 Elsevier B.V. All rights reserved.