Low-temperature sintering and microwave dielectric properties of LiF-doped CaMg1−xZnxSi2O6 ceramics

The diopside ceramics, CaMg1−xZnxSi2O6 (x=0–0.3), were synthesized via the solid-state reaction method. Zn2+ substitution for Mg2+ can markedly lower the densification temperature and improve the microwave dielectric properties of CaMgSi2O6 ceramics. For x=0.1, CaMg0.9Zn0.1Si2O6 ceramics, can be sintered at 1200 °C and exhibit good microwave dielectric properties of εr=7.88, Qf=76,100 GHz and τf=−22.5 ppm/°C. LiF addition was proved to be effective to lower the sintering temperature to ∼900 °C without degrading the dielectric properties apparently. The CaMg0.9Zn0.1Si2O6 ceramics doped with 0.6 wt% LiF can be sintered in the temperature range of 900–975 °C and have excellent dielectric properties of εr∼7.7, Qf∼70,000 GHz and τf∼−25 ppm/°C. With low sintering temperature and good dielectric properties, these LiF-doped diopside ceramics are promising materials for LTCC integration applications.