2018 Volume 126 Issue 6 Pages 434-439
In this paper, we investigated the effects of calcium contents on the sintering behaviors, phase composition, microstructure and microwave dielectric properties of Li2Zn3Ti4O12 (LZT) ceramics to find temperature stable and high quality factor (Q×f) microwave ceramics. The X-ray diffraction (XRD) results indicated the LZT and CaTiO3 co-existed with each other and formed a stable composite system when the calcium was added. Scanning electron microscopy photographs also demonstrated the existence of CaTiO3 phase, which were consistent with the XRD results. With the increasing calcium content, the apparent density decreased from 4.38 to 4.28 g/cm3, the dielectric constant (εr) increased from 19.3 to 23.9, Q×f decreased from 74344 to 42264 GHz, and the temperature coefficient of resonant frequency (τf) was significantly improved from −48 to +9.12 ppm/°C due to the increasing amount of CaTiO3 phase. At last, the (Li2Zn2.72Ti3.72O11.16)–0.28CaTiO3 ceramics sintered at 1200°C for 4 h displayed the excellent comprehensive properties of εr = 23.5, Q×f = 55604 GHz and τf = 0 ppm/°C.