Journal of the American Ceramic Society, Vol.90, No.3, 845-849, 2007
Low-temperature firing and microwave dielectric properties of Ca[(Li1/3Nb2/3)(0.84)Ti-0.16]O3-delta ceramics for LTCC applications
The effects of LiF and ZnO-B2O3-SiO2 (ZBS) glass combined additives on phase composition, microstructures, and microwave dielectric properties of Ca[(Li1/3Nb2/3)(0.84)Ti-0.16]O3-delta (CLNT) ceramics were investigated. The LiF and ZBS glass combined additives lowered the sintering temperature of CLNT ceramics effectively from 1150 degrees to 880 degrees C. The main diffraction peaks of all the specimens split due to the coexistence of the non-stoichiometric phase (A) and stoichiometric phase (B), which all possess CaTiO3-type perovskite structures. The transformation from A into B became accelerated with the increase of LiF or ZBS content. ZBS glass restrained the volatilization of lithium salt, which greatly affected the microstructures and microwave dielectric properties. CLNT ceramics with 2 wt% LiF and 3 wt% ZBS sintered at 900 degrees C for 2 h show excellent dielectric properties: epsilon(r)=34.3, Q x f=17 400 GHz, and tau(f)=-4.6 ppm/degrees C. It is compatible with Ag electrodes, which makes it a promising ceramic for low-temperature cofired ceramics technology application.