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 degrees C and exhibit good microwave dielectric properties of epsilon(r)=7.88, Qf=76,100 GHz and tau(f)=-22.5 ppm/degrees C. LiF addition was proved to be effective to lower the sintering temperature to similar to 900 degrees 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 degrees C and have excellent dielectric properties of epsilon r similar to 7.7, Qf similar to 70,000 GHz and tau(f)similar to-25 ppm/degrees C. With low sintering temperature and good dielectric properties, these LiF-doped diopside ceramics are promising materials for LTCC integration applications. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.