Phase composition and microwave dielectric properties of Mg-excess MgTiO3 ceramics

作者:Xue, Xiaomei; Yu, Hongtao*; Xu, Guangliang
来源:Journal of Materials Science: Materials in Electronics , 2013, 24(4): 1287-1291.
DOI:10.1007/s10854-012-0921-4

摘要

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 Q (f) value is very sensitive to the composition and it shows a non-linear variation corresponding to a relative amount of Mg. A very high Q (f) 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 Q (f) showed an initial increase, followed by a decrease, but epsilon(r) had been declining. The specimen with single MgTiO3 phase was obtained at the level of Mg/Ti = 1.02. A high Q (f) of 357,400 GHz (at 10 GHz) together with an epsilon(r) = 17 and tau (f) = -51 ppm/A degrees C for MgTiO3 ceramics (Mg/Ti = 1.02) were obtained at 1,390 A degrees C sintered for 4 h.