Sinterability and microwave dielectric properties of Li_2CO_3-V_2O_5 added Mg_4Nb_2O_9-CaTiO_3 composite ceramics

摘要

The effects of Li_2CO_3-V_2O_5 (LV) co-doped on the sinterability, phase eompositions and microwave dielectric properties of Mg_4Nb_2O_9-CaTiO_3 composite ceramics have been investigated. The phase compositions and microstructure were analyzed using X-ray diffraction, energy dispersive X-ray analysis and scanning electron microscopy techniques. The densification sintering temperature is lowed from 1275℃ to 1200℃ with an amount LV addition. For the specimen with 1.5 wt°o LV addition sintered at 1200℃ for 5 h exhibited dielectric properties: ε_r-23. Q·f 24 000 GHz (at 7.7GHz ), τ_f=1.0 ppm/℃. These properties were correlated with the formation of non-stoichiometric compound Mg_4(Nb_(1-x)Ti_x)_2O_(9-δ).