Quench Effects on Structural and Electrical Properties of the BFO-BT Based Lead-Free Piezoelectric Ceramics

Fabrication process usually has crucial effects on the properties of ceramics. In this work, we report effects of quenching process on the structural and electrical properties of the bismuth ferrite-barium titanate based lead-free piezoelectric ceramics (abbreviated as BFO-31BT). By comparison studies of the furnace-cooled, air-quenched and water-quenched ceramic samples, we find that the microstructure and domain configuration are significantly influenced by the quenched conditions. A dielectric thermal hysteresis is observed in the quenched samples, but is absence in the normal furnace-cooled samples. The BFO-31BT ceramic quenched in water at 800 °C shows superior ferroelectric properties with large P
r
= 46 μC/cm
²
, medium d
33
= 146 pC/N, and large ε
r
= 93580 at high T
c
= 459 °C. The dielectric anomalies and the enhancement of ferroelectric properties are attributed to the evolution of the domain structure by quenching treatment, which reduces the charge defects and increases the facility of domain wall motion.