Ultra-low temperature sintering microwave dielectric ceramics based on Ag2O-MoO3 binary system

The Ag2Mo2O7 and Ag6Mo10O33 ceramics for ultra-low temperature co-fired ceramic application were prepared by the solid-state reaction route. The optimized densification temperatures of Ag2Mo2O7 and Ag6Mo10O33 are 460 degrees C and 500 degrees C, respectively. The phase structures and microstructures of these ceramics were systematically studied. The Ag2Mo2O7 ceramic sintered at 460 degrees C/4 h exhibits excellent microwave dielectric properties with epsilon(r)=13.3, Qxf=25 300 GHz and (f)=-142 ppm/degrees C at 9.25 GHz. The Ag6Mo10O33 ceramic sintered at 500 degrees C/4 h shows the microwave dielectric properties with epsilon(r)=14.0, Qxf=8500 GHz and (f)=-50 ppm/degrees C at 9.00 GHz. Moreover, when Ag2Mo2O7 samples are sintered at ultra-low sintering temperatures of 420 degrees C-490 degrees C, the Qxf values of them are all above 20 000 GHz. Besides, the Ag2Mo2O7 ceramic does not react with silver powder or aluminum powder. The variation of relative permittivity, resonant frequency, and Qxf values as a function of operating temperature has been also studied. All the results indicate that the Ag2Mo2O7 ceramic is a good candidate for ultra-low temperature co-fired microwave devices.