Effect of zirconium deficiency on structure characteristics,morphology and microwave dielectric properties of Li2Mg3Zr1-xO6 ceramics

To suppress the impurity phases and porous microstructure caused by lithium volatilization, the Li₂Mg₃ZrO₆ and Zr-deficiency Li₂Mg₃Zr_1-xO₆ (x = 0.02, 0.04, 0.06, 0.08, 0.10) ceramics were successfully synthesized via the solid-state method assisted with atmosphere-controlled sintering. The influences of non-stoichiometric on structure characteristics, morphology and microwave dielectric properties of Li₂Mg₃Zr_1-xO₆ ceramics were investigated. The XRD and SEM results proved that the Zr-deficiency restrained the formation of impurity phases and remarkably improved the densification of Li₂Mg₃Zr_1-xO₆ samples. The variation trend of dielectric constant (ε_r) was explained by the relative density and theoretical dielectric polarizability. The quality factor (Q × f) was strongly associated with the impurity phases and relative density. Additionally, the temperature coefficient of resonant frequency (τ_f) showed the same trend as the total bond energy E_total, indicating the bond energy might play vital roles in thermal stability of Li₂Mg₃Zr_1-xO₆ samples. Typically, the Li₂Mg₃Zr_1-xO₆ sample obtained at x = 0.06 possessed remarkable dielectric performances: ε_r = 13.13, Q × f = 116,400 GHz (10.14 GHz) and τ_f = ?26.30 ppm/°C.