Phase compositions, microstructures, and microwave dielectric properties of Li₂Zn₃Ti₄O₁₂-based temperature stable materials modified by CaTiO₃ additions

In present work, the microwave dielectric properties of CaTiO₃-added Li₂Zn₃Ti₄O₁₂ ceramics prepared by the conventional solid-state method have been investigated. The phase composition, microstructure and microwave dielectric properties of (1 − x) Li₂Zn₃Ti₄O₁₂–x CaTiO₃ (x = 3, 4, 5, 6 and 7 wt%) ceramics were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDS and network analyzer. The XRD and EDS results indicated that the ceramics involved Li₂Zn₃Ti₄O₁₂ and CaTiO₃ phases. The SEM micrographs shown that as the CaTiO₃ contents increased, the average grain size of the composition ceramics decreased. The microwave dielectric properties of the composition ceramics can be effectively controlled by varying the CaTiO₃ contents. The values of dielectric constant (ε_r) and τ_f of the composition ceramics were increased, and the quality factor (Q × f) was decreased with increasing the CaTiO₃ contents. Typically, a new temperature stable microwave dielectric material of 0.94 Li₂Zn₃Ti₄O₁₂–0.06 CaTiO₃ with excellent microwave dielectric properties of ε_r = 21.7, Q × f = 61,490 GHz, and τ_f = + 2.68 ppm/°C was attained when sintered at 1175 °C for 4 h.