Densification, microstructure and microwave dielectric properties of ultra-low fire BaTe_4O_9-TiTe_3O_8 ceramic composites

摘要

In this study, BaTe_4O_9-TiTe_3O_8 ceramic composites with various amounts of TiTe_3O_8 were prepared, and the densification, microstructural evolution, and dielectric properties of the ultra-low fire ceramic composites were characterized. With the addition of TiTe_3O_8, the ceramic composites were densified at 575 °C with the maximum densities ranging from 93% to 96% of theoretical density. Except the BaTe_4O_9 and TiTe_3O_8 phases, no other second phase was observed in the XRD results. The change in the microstructures caused by the increase of TiTe_3O_8 content appeared to be insignificant. Wide grain size distributions with angular grains in the range of 1-4 mu m were observed for all cases. The best dielectric properties - ε_r value of 25, Q x/value of 19,340 GHz, and τ_f value of -2.7 ppm/°C - were obtained for BaTe_4O_9-40 wt% TiTe_3O_8 ceramic composite sintered at 575 °C, qualifying the ultra-low fire composites for use in the application of ceramic resonators.