Abstract: The ferroelectric property of ceramics can be significantly improved by adding (Ba_0.85Ca_0.15)(Zr_0.10Ti_0.90)O₃ into BiFeO₃. However, the sintering temperature of ceramics prepared by traditional solid-state method is high, resulting in increasing internal defects of ceramic materials. In this study, 0.7BiFeO₃-0.3(Ba_0.85Ca_0.15)(Zr_0.10Ti_0.90)O₃-0.15% (mass fraction) MnCO₃ (abbreviated as 0.7BF-0.3BCZT) ceramics were sintered using the two-step sintering method based on the short-term sintering at high temperature (T₁) and long-term holding at low temperature (T₂). The effect of T₁ temperature on the phase composition, microstructure, ferroelectric and dielectric properties of as-prepared ceramics was investigated. The results reveal that the phase structures of as-prepared ceramics are coexistence of rhombohedral and pseudo-cubic phases with no evidence of secondary phase. With the increase of T₁ sintering temperature, the bulk density, dielectric constant and remanent polarization of ceramics increase first and then decrease. Consequently, the ceramics prepared at T₁=1 040 ℃ demonstrate excellent dielectric and ferroelectric properties. The maximum dielectric constant and remanent polarization are 6 706.10 and 8.53 μC/cm², respectively.

Key words: BiFeO₃, (Ba_0.85Ca_0.15)(Zr_0.10Ti_0.90)O₃, ferroelectric ceramics, two-step sintering method, dielectric constant, polarization