Enhanced electromechanical properties of (Na1/2Bi1/2)TiO3-BaTiO3 lead-free piezoelectric ceramics through alternating current polarization

The piezoelectric and electromechanical properties of 0.94(Na1/2Bi1/2)TiO3-0.06BaTiO(3) (NBT-6BT) lead-free piezoelectric ceramic by alternating current polarization (ACP) and direct current polarization (DCP) methods were studied in this work. Results indicated that the thickness-mode electromechanical coupling coefficients (k(t)) of the NBT-6BT which located around the morphotropic phase boundary (MPB) was significantly improved with an enhancement ratio of 28.6% from 58.1% to 74.7% after ACP compared to DCP. The ferroelectric domain structure and phase structure of the samples after ACP and DCP were investigated using piezoresponse force microscopy and X-ray diffraction, which revealed that the k(t) enhancement is mainly originated from the higher domain wall density boosted by the ACP.

Automated summary

The piezoelectric and electromechanical properties of NBT-6BT lead-free piezoelectric ceramic were studied using AC polarization and DC polarization methods. The results showed that the thickness-mode electromechanical coupling coefficient (k(t)) of NBT-6BT near the MPB was significantly improved by AC polarization, with a 28.6% enhancement ratio. The enhancement was mainly due to the higher domain wall density boosted by AC polarization, as observed through piezoresponse force microscopy and X-ray diffraction.