Low-temperature sintering and microwave dielectric properties of Li₂TiO₃ based ceramics

New low sintering temperature and temperature-stable low-loss ceramics based on Li₂TiO₃ with lithium zinc borate (LZB) glass and LiZnNbO₄ doping have been prepared by the conventional solid-state reaction route. The effect of LZB glass addition on the sinterability, phase purity, microstructure, and microwave dielectric properties of Li₂TiO₃ ceramics has been investigated. The XRD results suggest the presence of single Li₂TiO₃ phases for LZB glass-added Li₂TiO₃ ceramics. The addition of LZB glass can effectively lower the sintering temperature to 900 °C, and does not induce much degradation of the microwave dielectric properties. Typically, the 2.0 wt% LZB glass-added ceramic sintered at 900 °C has better microwave dielectric properties of ε_r = 23.2, Q × f = 38,909 GHz, and τ _f  = 30.1 ppm/°C. Meanwhile, LiZnNbO₄ compound is selected to tune the temperature coefficient of resonant frequency (τ _f ) to near zero. It is found that the 2.0 wt% LZB glass-added Li₂TiO₃ ceramics with 35 wt% LiZnNbO₄ sintered at 925 °C have good microwave dielectric properties of ε_r = 20.7, Q × f = 19,366 GHz, τ _f  = −0.5 ppm/°C, which can find applications in microwave devices that require low sintering temperature.