THE SINTERING BEHAVIOUR, MICROSTRUCTURE AND MICROWAVE DIELECTRIC PROPERTIES OF Li₂Zn₃Ti₄O12 CERAMICS DOPED BY LiF

Li₂Zn₃Ti₄O12 ceramics were prepared by the traditional solid-state reaction method. The sintering behaviour, microstructure and microwave dielectric properties of the LiF doped Li₂Zn₃Ti₄O12 ceramics were studied by X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM) and a network analyser. When a small amount of LiF is added, LiF is a pure phase and the LiF and the Li₂Zn₃Ti₄O12 phase coexisted under co-firing conditions, which reduced the sintering temperature to 900̊C without weakening its microwave dielectric properties. With an increase in the LiF content, the apparent density increased from 3.81 g/cm³ to 4.17 g/cm³, the dielectric constant decreased from 17.9 to 16.4, and the Q×f value firstly increased from 2800 GHz to 47983 GHz and then decreased to 24944 GHz. The temperature coefficient of the resonant frequency was slightly decreased from -48 ppm/̊C to -54 ppm/̊C. Excellent combined microwave dielectric properties were obtained for the LiF-added composition with x = 1wt% with an εr of 17.9, a Q×f of 47983 GHz and a τf of -48.3 ppm/̊C when sintered at 900 °C for 4 h.