Ultra‐low temperature sintering microwave dielectric ceramics based on Ag 2 O–MoO 3 binary system

The Ag 2 Mo 2 O 7 and Ag 6 Mo 10 O 33 ceramics for ultra‐low temperature co‐fired ceramic application were prepared by the solid‐state reaction route. The optimized densification temperatures of Ag 2 Mo 2 O 7 and Ag 6 Mo 10 O 33 are 460°C and 500°C, respectively. The phase structures and microstructures of these ceramics were systematically studied. The Ag 2 Mo 2 O 7 ceramic sintered at 460°C/4 h exhibits excellent microwave dielectric properties with ε r =13.3, Q×f =25 300 GHz and τ f =−142 ppm/°C at 9.25 GHz. The Ag 6 Mo 10 O 33 ceramic sintered at 500°C/4 h shows the microwave dielectric properties with ε r =14.0, Q×f =8500 GHz and τ f =−50 ppm/°C at 9.00 GHz. Moreover, when Ag 2 Mo 2 O 7 samples are sintered at ultra‐low sintering temperatures of 420°C‐490°C, the Q×f values of them are all above 20 000 GHz. Besides, the Ag 2 Mo 2 O 7 ceramic does not react with silver powder or aluminum powder. The variation of relative permittivity, resonant frequency, and Q×f values as a function of operating temperature has been also studied. All the results indicate that the Ag 2 Mo 2 O 7 ceramic is a good candidate for ultra‐low temperature co‐fired microwave devices.