Study on 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 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 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 = 22,505 GHz, τ_f = −12.79 ×10⁻⁶/℃, 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.