烧结后退火对NBT-6.5BT准同型相界陶瓷储能性能的影响

In recent years, relaxor ferroelectric materials have attracted significant interest due to their tunable properties, enabling the demonstration of remarkable properties such as high energy storage and exceptional high-power capabilities. Ceramics of the lead-free piezoelectric MPB composition 0.935(Na 0.5 Bi 0.5 )TiO 3 -0.065BaTiO 3 (NBT-6.5BT), featuring varied crystallite sizes achieved through annealing at different temperatures and duration after conventional solid-state reaction methods, have been studied. The HRXRD analysis has confirmed the presence of monoclinic reflections acting as a bridging phase between rhombohedral and tetragonal phases. Additionally, HRTEM analysis has revealed an increase in PNRs, contributing to relaxor behavior, which was further evidenced in the frequency dispersion of permittivity that depends on temperature. Raman spectroscopy has attributed the persistence of the morphotropic phase boundary (MPB) to annealing and a decrease in covalent behavior. An increase in dielectric constant with annealing proves the occurrence of specific relaxor properties. Furthermore, the reduction in remnant polarization with increasing temperature has resulted in slim P-E loops, yielding an energy storage value of approximately 0.606 J/cm 3 with an efficiency of 80% in samples with an increased crystallite size of 46 nm. This study presents a novel approach to enhancing relaxor behavior through post-sintering annealing, thereby expanding the application potential of NBT-BT ceramics.