Crystal-oriented (Bi_0.5, Na_0.5)_0.85–Ba_0.15TiO₃ ceramics prepared by colloidal processing in rotating high magnetic field

Abstract

Crystal-oriented (Bi_0.5, Na_0.5)_0.85–Ba_0.15TiO₃ (BNBT15) ceramics with a perovskite crystal structure were prepared by colloidal processing in a rotating high magnetic field to improve their piezoelectric properties. The presence of BaTiO₃ leads to anisotropic crystal lattices, allowing crystal-oriented BNBT15 ceramics to be successfully fabricated, using a rotating magnetic field to orient the c- and a-axes of the crystal in the powder compact. The phase transformation that occurred during sintering redistributed the c-axis oriented structure along both the a- and c-axes. Again, the c-axis was enhanced by electrical field polarization. A piezoelectric constant of 122 pC/N was obtained, which is larger than the 88 pC/N of BNBT ceramics.