Structural Transformation of Hexagonal (0001)BaTiO₃Ceramics to Tetragonal (111)BaTiO₃Ceramics

Fabrication of Textured Ceramics Using Mn and Nb-doped Hexagonal BaTiO₃ by an Electrophoretic Deposition in a High Magnetic Field

“…F 0001 for the (0001)-oriented accumulations was calculated to be 40 %. In previous study, the accumulations have been prepared by a slip-casting in a high magnetic field [10]. We also prepared the accumulations by the slip-casting method in 12T, then F 0001 of the accumulations was 24 %.…”

“…The latter one is critical to improving the piezoelectric properties with the Mn and Nb doping method. An alternative approach to preparing oriented BT ceramic can be annealing undoped BT powder in H 2 atmosphere [10]. By doing this, tetragonal phase of BT transforms to a hexagonal phase.…”

“…In ref. [10], the hexagonal BT powder was accumulated by a slip-casting method. When the EPD method is used to prepare the oriented BT ceramics, a higher degree of the (111) orientation is expected, which leads an increased piezoelectric response.…”

“…The increased piezoelectric response has been attributed to an increased domain wall density in the small grains for BT ceramics. The other is preparation of crystallographically oriented BT ceramics [8][9][10]. At room temperature, BT has a tetragonal symmetry with a spontaneous polarization along the <001> directions.…”

“…On the other hand, hexagonal BT has a large c/a of 2.44. Actually, oriented BT ceramics were fabricated using hexagonal BT particles by slip-casting in a high magnetic field [10]. The hexagonal phase is stable at high temperature >1430°C for undoped BT prepared in air [18].…”