Effect of Li2O-V2O5 addition on the sintering behavior and microwave dielectric properties of Li3(Mg1-xZnx)2NbO6 ceramics

The effect of Zn2+ substitution on the structure and microwave dielectric properties of Li3Mg2NbO6 ceramic was investigated. The compositions of Li-3(Mg1-xZnx)(2)NbO6 (0 <= x <= 0.1) ceramics were prepared by the solid-state reaction method. The phase structure, microstructure and microwave dielectric properties of Li-3(Mg1-xZnx)(2)NbO6 ceramics were analyzed via an X-ray diffraction, a scanning electron microscope as well as a network analyzer. All samples sintered at 1080-1240 C for 4 h remained a single orthorhombic structure, which could be indexed according to the Li3Mg2NbO6 phase (JCPDS-PDF #86-0346). The microwave dielectric properties of Li-3(Mg1-xZnx)(2)NbO6 ceramics exhibited significant dependence on the sintering condition, microstructure and composition. Excellent microwave dielectric properties (epsilon(r)similar to 17.2, Q x f similar to 142,331 GHz, tau(f)similar to-23.2 ppm/degrees C) were obtained in the x=0.08 sample sintered at 1120 degrees C for 4 h in air. In addition, the 0.17Li(2)O-0.83V(2)O(5) composition was added as a sintering aid to lower the sintering temperature. The 0.5 wt% 0.17Li(2)O-0.83V(2)O(5) added Li-3(Mg0.92Zn0.08)(2)NbO6 ceramic showed fairly good microwave dielectric properties of epsilon r similar to 14, Q x f similar to 83,395 GHz, tau(f)similar to-37.2 ppm/degrees C when sintered at 925 C for 2 h. Furthermore, there was no chemical reaction between Ag electrode and the sintering aid added sample, which further demonstrates that the Li-3(Mg0.92Zn0.68)(2)NbO6 ceramic modified with 0.17Li(2)O-0.83V(2)O(5) would be a promising candidate material for low-temperature cofired ceramic (LTCC) applications. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.