Publication Date:
2014-11-04
Description:
The compounds in Na 2 O - MoO 3 system were prepared by the solid-state reaction route. The phase composition, crystal structures, microstructures, and microwave dielectric properties of the compounds have been investigated. This series of compounds can be sintered well at ultra-low temperatures of 505°C–660°C. The sintered samples exhibit good microwave dielectric properties, with the relative permittivities (ε r ) of 4.1–12.9, the Q × f values of 19900–62400 GHz, and the τ f values of −115 ppm/°C to −57 ppm/°C. Among the eight compounds in this binary system, three kinds of single-phase ceramics, namely Na 2 MoO 4 , Na 2 Mo 2 O 7 and Na 6 Mo 11 O 36 were formed. Furthermore, the relationship between the structure and the microwave dielectric properties in this system has been discussed. The average Na I - O and Mo VI - O bond valences have an influence on the sintering temperatures in Na 2 O - MoO 3 system. The large valence deviations of Na and Mo lead to a large temperature coefficient of resonant frequency. The X-ray diffraction and backscattered electron image results show that Na 2 MoO 4 doesn't react with Ag and Al at 660°C. Also, Na 2 Mo 2 O 7 has a chemical compatibility with Al at 575°C.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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