Effects of BaCu(B2O5) sintering additive on dielectric properties of CaO-Li2O-12Sm2O3-TiO2 microwave dielectric ceramics

The sintering temperature of 16CaO-9Li2O-12Sm2O3 -63TiO2 (CLST) ceramics was approximately 1300C, which was efficiently decreased with different amounts of BaCu(B2O5)(BCB) ceramic powder addition. The bulk density of the specimens increased and reached saturation with increasing temperature, and a high relative density about 96% was obtained for the 4% (in mass) BCB-added CLST ceramics sintered at 1050C for 2 h. The relative dielectric constant (Εr) increased initially and then decreased slightly with increasing BCB content. The dielectric loss (tan) value increased with the addition of BCB because of the presence of the liquid phase. The temperature coefficients of the resonance frequency (τf) value were closer to zero in comparison with the pure CLST ceramic. Good dielectric properties of Εr = 81, tan = 0.021 and τf = 0.5 × 10-6/°C (1 MHz) were obtained for the 4% BCB-added CLST ceramics sintered at 1050C for 2 h.