Low-temperature sintering and microwave dielectric properties of LiF-doped CaMg1−Zn Si2O6 ceramics

Abstract The diopside ceramics, CaMg 1− x Zn x Si 2 O 6 ( x =0–0.3), were synthesized via the solid-state reaction method. Zn 2+ substitution for Mg 2+ can markedly lower the densification temperature and improve the microwave dielectric properties of CaMgSi 2 O 6 ceramics. For x =0.1, CaMg 0.9 Zn 0.1 Si 2 O 6 ceramics, can be sintered at 1200 °C and exhibit good microwave dielectric properties of e r =7.88, Qf =76,100 GHz and τ f =−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 CaMg 0.9 Zn 0.1 Si 2 O 6 ceramics doped with 0.6 wt% LiF can be sintered in the temperature range of 900–975 °C and have excellent dielectric properties of er ∼7.7, Qf ∼70,000 GHz and τ f ∼−25 ppm/°C. With low sintering temperature and good dielectric properties, these LiF-doped diopside ceramics are promising materials for LTCC integration applications.