Low temperature sintering and microwave dielectric properties of (Zn_0.65Mg_0.35)TiO₃ ceramics with BiVO₄

The effects of BiVO₄ and CaTiO₃ additives on the microwave dielectric properties of (Zn,Mg)TiO₃ (ZMT) ceramics were investigated. BiVO₄ as a sintering agent could effectively lower the firing temperature of ZMT ceramics below 930 °C. From XRD analysis, the secondary phase formation occurred when BiVO₄ exceeding the solubility limit 2 wt% in ZMT matrix. SEM results indicated that due to the liquid phase sintering BiVO₄ significantly improved the grain growth and densification. With an increase of BiVO₄, the dielectric constant (ε_r) monotonously increased, but the quality factor (Qf) gradually decreased, and also the temperature coefficient of resonant frequency (τ_f) dramatically linear degraded. Besides, the addition of CaTiO₃ can adjust the τ_f value of this system to a near zero level. (Zn_0.65Mg_0.35)TiO₃ ceramic codoped with 1.5 wt% BiVO₄ and 5 wt% CaTiO₃ additives sintered at 930 °C exhibited the good microwave dielectric properties of ε_r = 23, Qf = 16177 GHz, τ _f ≈ 1.0 ppm/°C.