Low-temperature sintering and microwave dielectric properties of MgTiO3 ceramics

The effects of CuO-Bi2O3-V2O5 additions on the sintering temperature and the microwave dielectric properties of MgTiO3 ceramics were investigated systematically. The CuO-Bi2O3-V2O5 (CuBiV) addition significantly lowered the densification temperature of MgTiO3 ceramics from 1400 degrees C to about 900 degrees C, which is due to the formation of the liquid-phase of BiVO4 and Cu-3(VO4)(2) during sintering. The saturated dielectric constant (epsilon(r)) increased, the maximum quality factor (Qf) values decreased and the temperature coefficient of resonant frequency (tau(f)) shifted to a negative value with the increasing CuBiV content, which is mainly attributed to the increase of the second phase BiVO4. MgTiO3 ceramics with 6 wt.% CuBiV addition sintered at 900 degrees C for 2 h have the excellent microwave dielectric properties: epsilon(r)= 18.1, Qf = 20300 GHz and tau(f) = -57 ppm/degrees C.