Ultrahigh Q values and atmosphere-controlled sintering of Li2(1+x)Mg3ZrO6 microwave dielectric ceramics

Ultrahigh-Q Li2(1+x)Mg3ZrO6 microwave dielectric ceramics were successfully prepared by means of atmosphere-controlled sintering through simultaneously adopting double crucibles and sacrificial powder. This technique played an effective role in suppressing the lithium volatilization and further promoting the formation of the liquid phase, as evidenced by the X-ray diffraction, microstructural observation and the density measurement. Both dense and even microstructure, and the suppression of detrimental secondary phases contributed to low-loss microwave dielectric ceramics with Q×f values of 150,000-300,000 GHz. Particularly, desirable microwave dielectric properties of εr=12.8, Q×f=307,319 GHz (@9.88 GHz), and τf=−35 ppm/°C were achieved in the x=0.06 sample as sintered at 1275 °C for 6 h.