Microstructures and microwave dielectric properties of Li₂ZnTi₃O₈ ceramics prepared by reaction-sintering process

Abstract

The Li₂ZnTi₃O₈ ceramic was prepared by reaction-sintering process and its microwave dielectric properties were investigated. With increasing sintering temperature or dwell time, the relative densities, ε_r values and Q × f values of Li₂ZnTi₃O₈ ceramic increased initially and then decreased. The smaller τ_f value of Li₂ZnTi₃O₈ ceramic sintered at 975 °C was due to the low degree of oxygen octahedral distortion. When the sintering temperature exceeded 975 °C, the τ_f values of Li₂ZnTi₃O₈ ceramics were independent of sintering temperature. The tetragonal-shaped grains tend to appear in Li₂ZnTi₃O₈ ceramics sintered at higher temperature and longer dwell time, which was dominated by phase boundary reaction mechanism. Typically, The Li₂ZnTi₃O₈ ceramic sintered at 1,025 °C for 6 h had a maximum relative density of 97.4 % and good microwave dielectric properties of ε_r = 25.8, Q × f = 77,100 GHz, τ_f = −12.4 ppm/°C. The results show that the reaction-sintering process is a simple and effective method to produce dense Li₂ZnTi₃O₈ ceramics with excellent dielectric properties.