Dielectric properties of 0.95(Mg_(0.98)Zn_(0.02))TiO_3-0.05CaTiO_3 ceramic sintered by calcium borosilicate glass ceramic doping

摘要

The effect of calcium borosilicate (CBS) glass ceramic on the phase formation, the microstructures and the microwave dielectric properties of 0.95(Mg_(0.98)Zn_(0.02))-TiO_3-0.05CaTiO_3 (MZCT) ceramics prepared via the conventional solid-state reaction route were investigated. It has been found that (Mg_(0.98)Zn_(0.02))TiO_3 and CaTiO_3 are the main phases and a second phase (Mg_(0.98)Zn_(0.02))Ti_2O_5 appeared in MZCT ceramics doped with CBS glass. As the content of CBS glass increased, the second phase (Mg_(0.98)Zn_(0.02))Ti_2O_5 further enhanced. Appropriate CBS glass addition could effectively facilitate sintering of the ceramics, and well-densified microwave ceramics with uniform grains could be obtained under 1240 ℃. An extremely high Q × f of 59,200 GHz together with an ε_r of 21.42 and a τ_f value of -2.1 ppm/℃ could be found for 0.95(Mg_(0.98)Zn_(0.02))TiO_3-0.05CaTiO_3 specimen with 4 wt% CBS glass addition sintered at 1240 ℃ for 2 h. This study shows that appropriate addition of CBS glass could effectively decrease the sintering temperature of MZCT ceramics without deteriorating the ceramic performance.