Effect of CuO on the sintering and dielectric characteristics of (Ba_1−x Sr _x ) (Ti_0.9Zr_0.1)O₃ ceramics

Abstract

In order to lower the temperature required to density (Ba_1−x Sr _x ) (Ti_0.9Zr_0.1) O₃ (BSTZ-series) and to avoid the formation of a low dielectric constant phase, copper oxide is added as liquidphase promotor after BSTZ-series are calcined. Thea-axis lattice constant at room temperature elongates with both increasing amount of CuO added and higher sintering temperature, while thec-axis lattice constant elongates only slightly under the same condition. The dielectric constant increases with sintering temperature. However, for different amounts of CuO added, the dielectric constant increases with increasing amount of CuO at lower sintering temperatures (below ∼1100°C). When a higher sintering temperature is used (above ∼1200°C), the dielectric constant reaches a maximum at ∼1 wt % CuO added, and decreases slightly on further addition of CuO.