Low-temperature sintered (Zn_0.65Mg_0.35)TiO₃ microwave ceramics doped with CuV₂O₆

The influence of the CuV₂O₆ additives on the densification, microstructural evolution, and dielectric properties of (ZnMg)TiO₃ (ZMT) ceramics was investigated. The sintering agent CuV₂O₆ can significantly enhance the sinterability and lower the firing temperature of ZMT dielectrics to ≤930 °C. SEM shows that liquid phase sintering induced by CuV₂O₆ can promote the grain growth and elevate the bulk density dramatically. XRD indicates that excess CuV₂O₆ beyond the solubility ~1.5 wt% could form the secondary phase and affect the crystalline structure. The microwave results show that the dielectric constant (ε_r) increases gradually, but the quality factor (Q × f) and the temperature coefficients of resonant frequency (τ_f) decrease with increasing CuV₂O₆ content. Moreover, TiO₂ addition can effectively improve the microwave properties of CuV₂O₆-doped ZMT dielectrics and especially compensate the negative τ _f. (Zn_0.65Mg_0.35)TiO₃ ceramics codoped with 1 wt% CuV₂O₆ and 9 wt% TiO₂ sintered at 930 °C exhibited the optimum microwave dielectric properties: ε _r = 26.2, Q × f = 31,930 GHz, τ _f ≈ −0.32 × 10⁻⁶/°C.