Effect of BaCu(B2O5) on the sintering and microwave dielectric properties of Ca0.4Li0.3Sm0.05Nd0.25TiO3 ceramics

The sintering behaviors and microwave dielectric properties of the Ca0.4Li0.3Sm0.05Nd0.25TiO3 (abbreviated CLSNT) ceramics with different amounts of BaCu(B2O5) addition were investigated in this paper. Adding BaCu(B2O5) to CLSNT lowered its sintering temperature from 1300 °C to 925 °C. No secondary phase was observed in the CLSNT ceramics and complete solid solution of the complex perovskite phase was confirmed. The CLSNT ceramics with small amounts of BaCu(B2O5) addition could be well sintered at 925 °C without much degradation in the microwave dielectric properties. Especially, the 1.75 wt.% BaCu(B2O5)-doped CLSNT ceramic sample sintered at 925 °C for 3 h had optimum microwave dielectric properties of εr = 93.5 ± 3.2, Q × f = 6486 ± 434 GHz, and τf = 5 ± 1.5 ppm/°C (at 3-4 GHz), enabling it a promising candidate material for LTCC applications. Obviously, BaCu(B2O5) could be a suitable sintering aid to facilitate the densification and microwave dielectric properties of the CLSNT ceramics.