Microwave dielectric properties of low-temperature sinterable Ba_3(VO_4)_2-LiMgPO_4 composite ceramics

摘要

New (1-x)Ba_3(VO_4)_2-xLiMgPO_4 (x=0.40-0.60) microwave dielectric composite ceramics were prepared by sintering mixtures of Ba_3(VO_4)_2 and LiMgPO_4. The composite ceramics can be sintered in the temperature range of 850-875 ℃. Ba_3(VO_4)_2 and LiMgPO_4 coexist and no secondary phase is detected in the sintered bodies. Near-zero temperature coefficients of resonant frequency (τ_f) can be achieved by changing the relative content of the two phases, due to their opposite τ_f values. The composite ceramic with x=0.45 sintered at 850 ℃ shows desirable microwave dielectric properties of ε_r=9.67, Q×f= 50,700 GHz, and τ_f=+1.1 ppm/℃.