The preparation and properties of xLiVO₂-(1−x)Li₂TiO₃ composite microwave dielectric ceramics

To reduce the sintering temperature of lithium titanate-based microwave dielectric ceramics, this study successfully prepared xLiVO₂-(1−x)Li₂TiO₃ composite ceramics (with x ranging from 0.025 to 0.20) via a solid-phase sintering method. The sintering behavior and phase composition of the composite ceramics were systematically investigated under varying LiVO₂ additions and sintering temperatures, focusing on factors influencing dielectric properties and temperature stability. The results reveal that as the LiVO₂ content increases, the temperature coefficient of resonant frequency (τ_f) progressively decreases, shifting from positive to negative values. A near-zero τ_f was achieved at x=0.05. However, the LiVO₂ content critically impacts the quality factor, and excessive LiVO₂ significantly degrades the Q×f value (Product of quality factor and measured resonant frequency) of the xLiVO₂-(1−x)Li₂TiO₃ binary system. Furthermore, incorporating low-melting-point LiVO₂ substantially reduces the sintering temperature from 1200℃ (pure Li₂TiO₃) to 825—900℃. For the sample with x=0.075 sintered at 850℃, optimal properties were attained: Q×f=22505 GHz, τ_f=−12.79×10⁻⁶/℃, relative permittivity ε_r=27.47. This study successfully achieved xLiVO₂-(1−x)Li₂TiO₃ composite microwave dielectric ceramics with a low temperature coefficient of resonant frequency while significantly reducing the sintering temperature.