文摘
Lead-free and high-temperature 0.71BiFeO3-0.29BaTiO3 ceramics with Mn modification (BF-BT-x %Mn) were fabricated by conventional solid-state reaction method, and the high temperature dielectric, ferroelectric and piezoelectric properties were investigated. All compositions exhibited pseudo-cubic phases. Mn modification improved the electrical properties of BF-BT solid solutions at both room and high temperature. The Curie temperature TC, depolarization temperature Td, dielectric constant εr, dielectric loss tanδ, piezoelectric constant d33, electromechanical coupling factor kp, remnant polarization Pr of BF-BT-1.2 %Mn ceramics were 506, 500 °C, 556, 0.04, 169 pC N−1, 0.373, 31.4 μC cm−2, respectively. The εr, tanδ, and kp of BF-BT-1.2 %Mn ceramics were stable with the increase of temperature until 500 °C. The coercive field Ec of BF-BT-1.2 %Mn ceramics was nearly 30 kV cm−1 at 200 °C, which was much larger than those of PZT, BS-PT,BNT and KNN ceramics. The high field strain coefficient d*33 reached as large as 525 pm V−1 at 200 °C. These results showed that the BF-BT-x %Mn ceramics were promising candidate for high temperature piezoelectric applications.