Synthesis, characterization, and microwave dielectric properties of ixiolite-structure ZnTiNb₂O₈ ceramics through the aqueous sol–gel process

Highlights: • The nanosized ZnTiNb₂O₈ powders were obtained at 700 °C by the aqueous sol–gel process. • The ixiolite-structure ZnTiNb₂O₈ ceramics were sintered at 1050 °C for 4 h. • The microwave properties were ε_r = 35.3, Q ⋅ f = 66,700 GHz and τ_f = −55.4 ppm/°C. - Abstract: Microwave dielectric ceramics based on ixiolite-structure ZnTiNb₂O₈ were prepared by an aqueous sol–gel process. Highly reactive nanosized ZnTiNb₂O₈ powders with particle sizes of 30–50 nm were successfully obtained at 700 °C as precursors. Sintering characteristics and microwave dielectric properties of ZnTiNb₂O₈ ceramics were studied depending on sintering temperatures ranging from 950 °C to 1100 °C. The dielectric properties were strongly dependent on the compositions, the densifications and the microstructures of the specimens. With the increase of sintering temperature, density, ε_r and Q ⋅ f values were increased and saturated at 1050 °C with excellent microwave properties with an ε_r of 35.3, an high Q ⋅ f of 66,700 GHz, and a τ_f of −55.4 ppm/°C. The correlations of microstructure and dielectric properties for ZnTiNb₂O₈ ceramics were also investigated. The relatively low sintering temperature and high dielectric properties in microwave range would make these ceramics promising for application in electronics