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

Abstract The effect of Zn 2+ substitution on the structure and microwave dielectric properties of Li 3 Mg 2 NbO 6 ceramic was investigated. The compositions of Li 3 (Mg 1− x Zn x ) 2 NbO 6 (0≤ x ≤0.1) ceramics were prepared by the solid-state reaction method. The phase structure, microstructure and microwave dielectric properties of Li 3 (Mg 1− x Zn x ) 2 NbO 6 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 Li 3 Mg 2 NbO 6 phase (JCPDS-PDF #86-0346). The microwave dielectric properties of Li 3 (Mg 1− x Zn x ) 2 NbO 6 ceramics exhibited significant dependence on the sintering condition, microstructure and composition. Excellent microwave dielectric properties ( e r ~17.2, Q × f ~142,331 GHz, τ f ~−23.2 ppm/°C) were obtained in the x =0.08 sample sintered at 1120 °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 (Mg 0.92 Zn 0.08 ) 2 NbO 6 ceramic showed fairly good microwave dielectric properties of e r ~14, Q × f ~83,395 GHz, τ f ~−37.2 ppm/°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 (Mg 0.92 Zn 0.08 ) 2 NbO 6 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.