Electromechanical properties of flash sintered BNT-based piezoelectric ceramic

Lead-free, (BiNa _0.88 K _0.08 Li _0.04 ) _0.5 Ti _0.995 Mn _0.015 O ₃ piezoceramic has been successfully densified by a novel electrical current applied technique known as flash sintering (FS) at 880 °C. The effect of alternating and direct current, current density limit and holding time on the densification, crystal structure, electromechanical and electrical properties have been investigated. The optimum flash condition was obtained with a 1 KHz alternating current, 100 V·cm ⁻¹ initial electric field and preset maximum current limit of 1.5 A·cm ^-2 . The flash sintered specimen is characterized with finer grain size (10–15 μm), slightly higher electromechanical properties and higher symmetry butterfly shape strain hysteresis loop compared to conventional sintering. Under both sintering conditions uniform distribution of elements and pure rhombohedral structure were observed. Flash sintering also results in lower resistivity and more significant grain boundaries contributions in the conduction mechanism.