Effect of SiO2 addition on the microstructure and microwave dielectric properties of ultra-low fire TiTe3O8 ceramics

In this study, calcined TiTe3O8 powder mixed with different amounts of SiO2 was sintered at various temperatures. The effect of SiO2 addition on the densification, microstructural evolution and dielectric properties of TiTe3O8 was investigated. Results indicate that SiO2 addition inhibited the grain growth of TiTe3O8 and reduced the evaporation of TeO2. TiTe3O8 ceramics with 1 wt% SiO2 addition and sintered at 750 °C possesses the best dielectric properties: ɛr value of 47.6, Q × f value of 48,800, and τf value of +152 ppm/°C. Excess SiO2 addition results in the poor densification and the existence of secondary phase (SiO2) dissolved in a small amount of TeO2. They degrade the dielectric properties and trade off the benefit from the SiO2 addition.