关键词: Ca_0.3(Li_1/2Sm_1/2)_0.7TiO₃, Na₂O-CaO-B₂O₃, 低温烧结, 微波介质陶瓷

Abstract: The NCB(Na₂O-CaO-B₂O₃)-doped _Ca0.3(Li_1/2Sm_1/2)_0.7TiO₃(CLST) ceramics were fabricated via the traditional ceramic process. The relation between NCB dopant contents and the crystal structure, microstructure, sintering behavior, and dielectric properties of CLST ceramics were investigated systematically. The results indicate that the second phases are not found when NCB dopant contents are in the range from 1wt% to 15wt% and the major phase of CLST ceramics is still orthorhombic perovskite. With the increase of NCB content, the densification temperature and bulk density of CLST ceramics decrease, the dielectric constant ε_r and the product of quality factor and resonance frequency Qf value also decrease, and the temperature coefficient of resonant frequency τ_f increases to positive. NCB can effectively decrease the sintering temperature of CLST from 1300℃ to 900℃. The sample of CLST with 12.5wt% NCB sintered at 900℃ for 5h still has excellent dielectric properties: ε_r=73.7, Qf=1583GHz, τ_f=140.1×10-6/℃, which satisfies the design demand of high dielectric constant and multilayer microwave components.

Key words: Ca_0.3(Li_1/2Sm_1/2)_0.7TiO₃, Na₂O-CaO-B₂O₃, low-temperature sintering, microwave