The phase composition and microwave dielectric properties of Mg-excess MgTiO3 (Mg/Ti = 1, 1.02, 1.04, 1.05, 1.07) ceramics prepared via the conventional solid-state reaction route were investigated. A slight deviation from stoichiometry does not practically affect the relative permittivity and temperature coefficient of resonant frequency of the specimen. However, the Qf value is very sensitive to the composition and it shows a non-linear variation corresponding to a relative amount of Mg. A very high Qf can be achieved for specimen with single MgTiO3 phase, which can be obtained within the suitable composition. As the increasing of Mg content, the MgTi2O5 phase which was derived from Mg/Ti = 1 was disappeared, and when it exceeded 1.02, the phase of Mg2TiO4 emerged. Along with the augmentation of Mg/Ti, the bulk density and Qf showed an initial increase, followed by a decrease, but εr had been declining. The specimen with single MgTiO3 phase was obtained at the level of Mg/Ti = 1.02. A high Qf of 357,400 GHz (at 10 GHz) together with an εr = 17 and τf = −51 ppm/°C for MgTiO3 ceramics (Mg/Ti = 1.02) were obtained at 1,390 °C sintered for 4 h.
Resonant Frequency Dielectric Loss Microwave Dielectric Property Grain Morphology MgCO3
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This work was supported by the Ph. D. fund (No. 09zx7104) of Southwest University of Science and Technology.
Y.M. Miao, Q.L. Zhang, H. Yang et al., J. Mater. Sci. Eng. 128(13), 103 (2006)Google Scholar