Sintering characteristics, crystal structure, and microwave dielectric properties of Ce2[Zr1-x(Al1/2Nb1/2)x]3(MoO4)9 ceramics

Abstract

This work prepared a new type of Ce2[Zr1-x(Al1/2Nb1/2)x]3(MoO4)9 (CZ1-x(AN)xM) (x = 0.02–0.10) microwave dielectric ceramics through the solid-phase process. CZ1-x(AN)xM ceramics exhibited low dielectric constant, ultra-low dielectric loss, and near-zero resonant frequency temperature coefficient, which is suitable for 5 G technology. The effects of (Al1/2Nb1/2)4+ replacing Zr4+ on the sintering characteristics, crystal structure, and microwave dielectric properties of Ce2Zr3(MoO4)9 (CZM) ceramics were studied systematically. In this work, CZ1-x(AN)xM could form a pure crystal structure in the whole doping range according to the X-ray diffraction pattern. The crystal cell parameters of the ceramics were confirmed by Rietveld refinement analysis. Furthermore, the surface morphology of CZ1-x(AN)xM sintered at the optimum sintering temperature was studied by scanning electron microscopy. Some internal parameters of the ceramics were calculated and analyzed by employing the P-V-L theory. The theoretical loss was acquired by employing an infrared reflection spectrometer. When x was 0.04 and the sintering temperature was 850 ℃, the best properties were achieved, including εr = 10.54, Q·f = 91,476 GHz (at 9.55 GHz), and τf = − 8.95 ppm/℃. This work studied the relationship between lattice vibration and microwave dielectric properties and discussed the influence of ion doping on microwave dielectric properties from the perspective of chemical bonds, laying a theoretical foundation for related research.