Low temperature sintering and microwave dielectric properties of Li₂O–3ZnO–5TiO₂ ceramics doped with V₂O₅

Novel low-temperature sinterable Li₂O–3ZnO–5TiO₂ (LZT135) ceramics were prepared through a solid-state reaction method. XRD and EDS results showed that the LZT135 ceramics formed solid solutions with a crystal structure similar to Zn₂Ti₃O₈. The addition of V₂O₅ could decrease the sintering temperature of LZT135 ceramics to about 900 °C. When 0.6 wt% V₂O₅ was added, the LZT135 ceramics exhibited dielectric properties with relative permittivity (ε_r) = 20.2, quality factor (Q×f) = 59,000 GHz, and temperature coefficient of resonant frequency (τ_f) = − 30.2 ppm/°C at a sintering temperature of 900 °C. However, the τ_f value was still too high for industrial applications; therefore, TiO₂ was added to the LZT135 ceramics to further adjust the τ_f value. Finally, near-zero τ_f values and simultaneously desirable Q×f values were maintained for the low-temperature sintered LZT135 ceramics. The LZT135 ceramics doped with 0.6 wt% V₂O₅ and 6 wt% TiO₂ exhibited reasonably good microwave dielectric properties with ε_r = 24.3, Q×f = 51,700 GHz, and τ_f = 0.3 ppm/°C when sintered at 900 °C, thus showing a great potential for low-temperature co-firing ceramic applications.