Effect of Zn2+Substitution on Sintering Behavior and Dielectric Properties of NdNbO4 Ceramics

The effects of Zn2+ substitution on the sintering behavior and dielectric properties of Nd1-xZnxNbO4-x/2 ceramics were investigated. The synthetic process and phase evolution were studied using TG-DSC and X-ray diffraction (XRD) analysis. The results show that Zn2+ substitution lowers the densification temperature of NdNbO4 ceramics. A single phase of monoclinic NdNbO4 was obtained by appropriate substitution (x = 0.05) of Zn2+ for Nd3+ in NdNbO4 ceramics. As the Zn2+ content increased to x = 0.1, ZnNb2O6 phase appeared in the ceramic. The dielectric constant epsilon r increased slightly from 17 to 19 with the content of Zn2+ increasing from 0 to 0.2 mol. The quality factor Qxf firstly increased and then decreased and reached the highest values of Qxf = 60,000 GHz at x = 0.1. The temperature coefficient of resonant frequency f shifted from -37 ppm/degrees C to -45 ppm/degrees C with the Zn2+ content increasing.