Dielectric properties of low-firing Bi₂Mo₂O ₉ thick films screen printed on Al foils and alumina substrates

Low-firing Bi₂Mo₂O₉ thick films with a thickness of 15-20 μm were screen printed on Al foils and alumina substrates by screen-printing technology. The phase evolution, morphologies, and dielectric properties of the thick films were investigated. The thick films showed a pure Bi₂Mo₂O₉ phase at temperatures below 610°C. A mixture of Bi₂MoO₆, Bi₂Mo₃O ₁₂, and Bi₂Mo₂O₉ phases was found in the thick films sintered at 610°C and higher temperatures. The Bi ₂Mo₂O₉ thick films on Al foils sintered at 645°C showed excellent dielectric properties with a relative permittivity of 38 and a dielectric loss of 0.7% at 5 MHz. At the microwave frequency range from 5 to 19 GHz, the Bi₂Mo₂O₉ thick films on alumina substrates sintered at 645°C had a relative permittivity of ∼35 and Q × f of ∼12 500 GHz. It indicates that the Bi₂Mo ₂O₉ composition as potentially useful for low-temperature cofired ceramic using Al electrode.