Sintering characteristics, crystal structure and dielectric properties of cobalt-tungsten doped molybdate-based ceramics at microwave frequency

In this study, a sequence of Ce₂[Zr_1-x(Co_1/2W_1/2)_x]₃(MoO₄)₉ (CZ_1-x(CW)_xM) (x = 0.02–0.10) ceramics with excellent microwave dielectric properties were obtained by the traditional solid-phase method. The crystal structure, dielectric properties, and chemical bond characters of the ceramics were characterized and analyzed. X-ray diffraction and Rietveld refinement analysis show that CZ_1-x(CW)_xM could form a single-phase of the triangular crystal system in the entire doping range. The microstructure of the ceramic samples was obtained by scanning electron microscopy. The sintering temperature was reduced and the gain of the sample was refined as the increase of doping ion content. Furthermore, the intrinsic factors affecting the properties of CZ_1-x(CW)_xM were analyzed by employing P-V-L theory and through in-depth infrared analysis. When x was 0.04 and the sintering temperature was 750 ℃, the best dielectric properties of the samples were achieved, including ε_r = 9.95, Q·f = 80, 803 GHz (at 9.99 GHz), and τ_f = − 9.10 ppm/℃.