Influence of Mg2+ substitution on the crystal structure and microwave dielectric properties of ZnZrNb2O8 ceramics

Wolframite-structured Zn 1-x Mg x ZrNb 2 O 8 (0 ≤ x ≤ 0.1) ceramics were synthesized by the conventional solid-state method. The effects of Mg 2+ substitution on the sinter ability, crystal structures and microwave dielectric properties were systematically investigated. The Q·f values increased from 46,800 GHz to 53,400 GHz when the x value increased from 0 to 0.1. Based on the complex chemical bond theory, the intrinsic parameters were calculated to analyze the mechanism of dielectric loss in Zn 0.9 Mg 0.1 ZrNb 2 O 8 . The total lattice energy and bond energy of the Zn 0.9 Mg 0.1 ZrNb 2 O 8 were higher than that of ZnZrNb 2 O 8 , which was corresponding with the decrease of dielectric loss in the wolframite-structured compounds. The dielectric constant ( ε r ) and temperature coefficient of resonant frequency ( τ f ) of Zn 1-x Mg x ZrNb 2 O 8 ceramics were also heavily influenced by the addition of Mg 2+ . Typically, the dense Zn 0.9 Mg 0.1 ZrNb 2 O 8 ceramics sintered at 1200 °C exhibited excellent microwave dielectric properties with ε r  = 27.82, Q·f  = 53,400 GHz and τ f  = −45.82 ppm/°C.