High curie temperature BiFeO_3-PbTiO_3-Bi(Zn_(1/2)Ti_(1/2))O_3-PbZrO_3 piezoceramics with good thermal stability

摘要

MPB compositions of (0.80 - x)BiFeO_3-(x)PbTiO_3-0.15Bi(Zn_(1/2)Ti_(1/2))O_3-0.05PbZrO_3 (BF-PT-BZT-PZ) ceramics were designed (x = 0.26, 0.28, 0.30) and prepared by the conventional solid state reaction method. The microstructure, ferroelectric, dielectric, piezoelectric properties and thermal degradation were investigated. Typical saturated P-E hysteresis loops were obtained, presenting remnant polarization P_r of 30 μC/cm~2 and large coercive field E_c of 70 kV/cm. The dielectric and piezoelectric properties increased with PT contents, and the x = 0.30 samples had dielectric constant ε_(33)~T/ε_0 = 365, loss of tanδ = 0.017, piezoelectric coefficient of d_(33) = 85 pC/N, and Curie temperature of T_c ～ 550 ℃. Thermal annealing investigation showed that all of the three compositions had high temperature stability, and the thermal depolarization temperature of T_d was ～450 ℃.