Low-temperature sintering and electric properties of BCT-BZT and BCZT lead-free ceramics

摘要

Dielectric, ferroelectric, and piezoelectric properties between 0.33Ba_(0.8)Ca_(0.2)TiO_3-0.67BaTi_(1-x)Zr_xtO_3 (BCT-BZT) and Ba_(0.934)Ca_(0.066)Ti_(1-x)Zr_xO_3 (BCZT) lead-free ceramics, which were sintered at 1260 ℃ in atmosphere with different as-prepared nanoparticles, were studied. XRD results showed the evidence of the phase transitions and morphotropic phase boundary (MPB) regions of BCT-BZT and BCZT ceramics. The phase transitions in the triple point showed a sensitive variation of electric properties around MPB regions. The excellent electric properties (ε_r = ～9000, P_r = 35.6 μC/cm~2, and d_(33) = ～ 240 pC/N) were found in BCT-BZT ceramics. Spontaneous polarization states, defect dipole, and pinch effect were considered to be the important factors that influenced the electric properties. Moreover, study on the excellent electric properties around the triple point of BaTiO_3-based ceramics by different process would give a proposal for their practical production.