Piezoelectric Properties of NaNbO3-BaTiO3 Ceramics

(1-x)NaNbO₃-xBaTiO₃, (NNBTx; x=0.0-0.21) solid-solution ceramics were synthesized and their crystal structure, dielectric properties and piezoelectric properties were investigated. The crystal structure of NNBTx was varied from orthorhombic to tetragonal with increasing BaTiO₃ content x. The morphotropic phase boundary at room temperature was observed between x=0.08 and 0.09, and the lattice anisotropy and Curie temperature in the tetragonal phase decreased with increasing x. The highest electromechanical coupling factor, k _p , of 0.318 and the largest piezoelectric constant, d ₃₃, of 164 pC/N were obtained for NNBT0.09 with the tetragonal phase, and the highest mechanical quality factor of 890 was obtained for NNBT0.06 with the orthorhombic phase.