Low-temperature sintering and microwave dielectric properties of Ca(Li1/3Nb2/3)O3-δ ceramics

Effects of B2O3 and/or Bi2O3 on the sinterability and microwave dielectric properties of nonstoichiometric Ca(Li1/3Nb2/3)O3-delta(CLN) ceramics were investigated. With the addition of B2O3 from 0.5wt% to 4.0 wt%, the dielectric constant (K) and Q . f value of CLN sintered at 990 degreesC were as good as those of pure CLN sintered at 1150 degreesC. These results are due to the enhancement of the apparent density of CLN at low temperature by liquid phase sintering with compositional modification of Ca(Li1/3Nb2/3)O3-delta. However, the dielectric properties of the specimens with 6.0 wt% B2O3 decreased significantly due to the formation of a secondary phase, Li2B4O7. The sintering temperature of CLN was further reduced by Bi2O3 at the expense of the Q . f value. Typically, K of 30.6, Q . f of 31000 GHz, and TCF of -17.5 ppm/degreesC were obtained for the specimens with 4.0wt% B2O3 sintered at 1000 degreesC.