Dielectric properties of BNT-xBT prepared by hydrothermal process

Abstract

The BNT ceramic sample might be a good replacement for PZT piezoelectric in industrial applications, especially in energy harvesting from crystal vibrations. In order to enhance the performance of BNT ceramic, the solid solution was chosen by substitution with Ba+2 at Morphtropic Phase Boundary (MPB). The BNT-xBT powders with x=1, 0.07, 0.06 and 0 were prepared by the hydrothermal method with average particle size (65–150nm) at (90∘C/72h). The ceramic disc was sintered at (1150∘C/4h) and showed excellent relative density of about 96%. The results of X-ray diffraction (XRD) confirmed the MPB for x=0.06 and 0.07, while the BNT had a rhombohedral structure and BT had a tetragonal structure. The dielectric measurements showed that BNT, BNT-7BT, BNT-6BT behave as the relaxator ferroelectric and showed a strong dependence on frequency, especially in the MPB region while BT behaves as a normal ferroelectric. Both the Curie temperature and depolarization temperature decrease at the MPB region and showed strong dependency on frequency.

Keywords

• Ferroelectric behavior
• piezoelectric behavior
• energy harvesting
• hydrothermal process