Microwave dielectric properties of (1-x)ZnMoO4-xTiO2 composite ceramics

(1 - x)ZnMoO4-xTiO(2) (x = 0.0, 0.05, 0.158, 0.25, and 0.35) composite ceramics were synthesized by the conventional solid state reaction process. The sintering behavior, phase composition, chemical compatibility with silver, and microwave dielectric properties were investigated. All the specimens can be well densified below 950 degrees C. From the X-ray diffraction analysis, it indicates that the triclinic wolframite ZnMoO4 phase coexists with the tetragonal rutile TiO2 phase, and it is easy for silver to react with ZnMoO4 to form Ag2Zn2(MoO4)(3) phase and hard to react with TiO2. When the volume fraction of TiO2 (x value) increasing from 0 to 0.35, the microwave dielectric permittivity of the (1 - x)ZnMoO4-xTiO(2) composite ceramics increases from 8.0 to 25.2, the Q(f) value changes in the range of 32,300-43,300 GHz, and the temperature coefficient tau(f) value varies from - 128.9 to 157.4 ppm/degrees C. At x = 0.158, the mixture exhibits good microwave dielectric properties with a epsilon(r) = 13.9, a Q(f) = 40,400 GHz, and a tau(f) = + 2.0 ppm/degrees C. (C) 2011 Published by Elsevier B.V.