Processing optimization and field-induced strain response in laminated 0.6(Bi0.85La0.15) FeO3-0.4PbTiO3 ceramics

0.6(Bi_0.85La_0.15)FeO₃-0.4PbTiO₃ (BLF-PT) ceramics with pure perovskite structure were produced and laminated from a non-aqueous tape casting method. The effects of pressure and temperature, during the tapes lamination process, on the bulk density, ferroelectric and piezoelectric properties of BLF-PT ceramics were systematically investigated. The field-induced strain level and remnant polarization P_r of the laminated BLF-PT ceramics increased while the dielectric loss tanδ decreased with the rising of lamination temperature from 30 to 90°C due to the stronger combination between the ceramic tapes and relative higher bulk density. On the contrary, with the rising of lamination pressure from 30 to 150 MPa, The field-induced strain level and P_r first increased and then decreased. The dielectric constant and loss, remnant polarization, strain, and high field piezoelectric constant of BLF-PT ceramics obtained under optimal conditions are 409, 1.4% at 1 kHz, 33 μC/cm², 0.07% and 141 pm/V (S_max/E_max) at 50kV/cm, respectively. The results show that the laminated ceramics derived from tapes casting method exhibit comparable dielectric, ferroelectric and piezoelectric properties to those prepared by conventional powder forming technique, which is the basic step for the continuous developing for piezoelectric devices with multilayered or graded structure.