Effect of the template particles size on structure and piezoelectric properties of 〈0 0 1〉-textured BNT-based ceramics

This research investigated the effect of Bi 4 Ti 3 O 12 (BiT) template particles size on the structure and piezoelectric properties of 〈001〉-textured (Bi 0.5 Na 0.5 )TiO 3 (BNT)-based lead-free piezoelectric ceramics. Results of X-ray diffractometer analyses and scanning electron microscopy observations showed that high purity BiT template particles could be obtained with the KCl as the molten salt system. Highly 〈001〉-textured (~87%) BNT-based ceramics prepared with large size BiT templates (7.75 µm) exhibited a high inverse piezoelectric constant d 33 * (1100 pm/N), which was ∼3.38-fold larger than that with 1.91 µm (325 pm/N). In addition, we have found that too small the template size can make it difficult to align the orientation of the template during the casting process, whereas too large the size can create problems such as too much hysteresis (∆ S / S max = 67%). This study has demonstrated that the use of high purity large size BiT template particles could provide a feasible route to fabricate BNT-based textured ceramics with desired electro-strain properties.