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 °C to about 900 °C, which is due to the formation of the liquid-phase of BiVO₄ and Cu₃(VO₄)₂ during sintering. The saturated dielectric constant (ε_r) increased, the maximum quality factor (Qf) values decreased and the temperature coefficient of resonant frequency (τ_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 °C for 2 h have the excellent microwave dielectric properties: ε _r= 18.1, Qf = 20300 GHz and τ_f = −57 ppm/ °C.