Microstructure and electrical properties of textured Bi-layered Bi3TiNbO9 piezoceramics

Highly-textured Bi3TiNbO9 (BTNO) piezoelectric ceramics (the grain orientation degree of similar to 0.75) were prepared by the hot-forging method. X-ray diffraction results showed the pattern perpendicular to the hot-forging direction exhibiting strong (001) diffraction peaks. Scanning electron microscopy images showed that the plate-like grains were piled up along the forging axis. These indicate that the samples were highly oriented after forging. Dielectric, ferroelectric and piezoelectric properties, exhibited remarkable anisotropy in the hot-forged BTNO samples: the dielectric - constant (epsilon(r) ), remanent polarization (P,) and piezoelectric constant (d(33)) in the direction perpendicular (1) to the hot-forging axis were higher than those in the direction parallel (//) to the hot-forging axis. The ratio of epsilon(r)[perpendicular to]/epsilon r [//] was about 4.35 at Curie point (T-c) 913 degrees C, while those of P-r [perpendicular to]/P-r [//] and d(33)[perpendicular to]/d,33[//] were about 14 and 50, respectively.