Ferroelectric properties of lithia-doped (Bi0.95Na0.75K0.20)0.5Ba0.05TiO3 ceramics

Lead-free piezoelectric (Bi0.95Na0.75K0.20−xLix)0.5Ba0.05TiO3 ceramics have been prepared by conventional process for different lithium substitutions. The SEM images show that the ceramics are well sintered at 1428 K. Dielectric and ferroelectric measurements have been performed. With the increasing of lithium substitution, the Curie temperature of the (Bi0.95Na0.75K0.20−xLix)0.5Ba0.05TiO3 ceramics shifts from 570 K to 620 K, but the maximum value of the dielectric constant decreases from 6700 to 4700 correspondingly. A relatively larger remanent polarization of 36.8 μC/cm2 has been found in the x = 0.05 sample. The coercive field decreases as the lithium substitution amount increases. An optimized d33 = 194 × 10− 12 C/N and a relative dielectric constant εr = 1510 have been obtained in (Bi0.95Na0.75K0.15Li0.05)0.5Ba0.05TiO3.