Piezoelectric Properties of Bismuth Layer-Structured Ferroelectric Na0.5Bi4.5Ti4O15 Ceramic

Piezoelectric properties of the grain-oriented Na0.5Bi4.5Ti4O15 (NBT) ceramic, belong to the bismuth layerstructured ferroelectric (BLSF) ceramics are studied from applicational viewpoints on grain orientation prepared by the hot-forging (H.F.) method. The MnCO3 (0.1 wt%) doped NBT (NBT+Mn(0.1)) ceramic can stand the high temperature poling process, because of the high resistivity. The grain orientation (H.F.) makes the piezoelectric properties of NBT+Mn(0.1) ceramic much more pronounced than those of the non-oriented (O.F.) ceramic. Coupling factors k33 and k15, along with piezoelectric constants d33, d15, g33 and g15, of the H. F. NBT+Mn(0.1) ceramic are enhanced, and their anisotropies in k33/k31 and k15/k24 are emphasized. A bulk wave delay line oscillator using the ceramic substrate is demonstrated.