Dielectric Properties and Low‐Temperature Sintering of the Ba _0.6 Sr _0.4 TiO ₃ Ceramics with B ₂ O ₃ / CuO Additions

The sintering behaviors and dielectric properties of Ba _0.6 Sr _0.4 TiO ₃ ceramics were investigated as a function of B ₂ O ₃ and CuO content. The addition of both B ₂ O ₃ and CuO reduced the sintering temperature of Ba _0.6 Sr _0.4 TiO ₃ about 500°C. It was suggested that a liquid phase BaCu ( B ₂ O ₅ ) was formed and assisted the densification of Ba _0.6 Sr _0.4 TiO ₃ ceramics. Ba _0.6 Sr _0.4 TiO ₃ ceramics co‐doped with 3.0 mol% B ₂ O ₃ , and 2.0 mol% CuO , sintered at 950°C for 5 h, had a dense microstructure and showed good microwave dielectric properties of a moderate dielectric constant (ε = 1048), low dielectric loss (0.0090) and high tunability (42.2%) at dc electric field of 30 kV /cm.