A novel microwave dielectric ceramic Li₂NiZrO₄ with rock salt structure

Low loss Li₂NiZrO₄ ceramics with rock salt structure were successfully prepared by the solid-phase reaction method. The relationship between sintering temperature, phase composition and dielectric properties of Li₂NiZrO₄ ceramics was reported for the first time. The grain size gradually increased and the porosity decreased with the sintering temperature increasing. When the sintering temperature exceeds 1300 °C, the grains grow abnormally and some grains begin to melt. The XRD patterns indicated the second phase ZrO₂ appeared due to the volatilization of lithium. The grains grow abnormally and a second phase of ZrO₂ increased the loss of Li₂NiZrO₄ ceramics. The samples sintered at 1300 °C possessed the best dielectric properties: ε _r = 12.3, Q _f = 20000 GHz, τ _f = -23.4 ppm °C^-1, which would make the ceramic a possible candidate for millimeter-wave applications.