Structure-property relationships in temperature stable low firing Ag₂Mo₂O₇-Ag_0.5Bi_0.5MoO₄ microwave dielectric ceramics

In this work, a series of temperature stable dielectric ceramics with an ultra-low sintering temperature (480 °C) have been prepared through mixing Ag_0.5Bi_0.5MoO₄ with Ag₂Mo₂O₇. The XRD and SEM-EDS analysis reveal that the two phases could coexist. The microwave dielectric properties of diphase ceramics are calculated that are in a good agreement with the experimental data. Raman and infrared spectroscopic techniques are used to study the structure-property relationships from the point of the polarization mechanism. When the amount of Ag_0.5Bi_0.5MoO₄ is 0.65, the composite ceramics sintered at 480 °C show the best temperature stability with ε_r = 25.7, Q × f = 16 400 GHz, tanδ = 4.31 × 10⁻⁴, and τ_f = 0.3 ppm/°C. In addition, the ceramics exhibit good chemical compatibility with aluminum. These results indicate that (1-x) Ag₂Mo₂O₇-xAg_0.5Bi_0.5MoO₄ ceramics show the excellent temperature stability among those with a sintering temperature as low as 500 °C and could be good candidates for microwave device applications.