Temperature insensitive piezoelectric properties on the morphotropic phase boundary of BaZrO3-modified lead-free KNN-BLT ceramics

The formation of a morphotropic phase boundary (MPB) in piezoelectric ceramics is one of the most important techniques to enhance their dielectric and piezoelectric properties. In this work, a rhombohedral (R) and tetragonal (T) phase boundary has been designed and clarified using the lead‒free 0.92(Na 0.5 K 0.5 )NbO 3 –(0.08– x )(Bi 0.5 Li 0.5 )TiO 3 – x BaZrO 3 ternary system. The R-T phase coexistence region is identified in the ceramics with 0.06 ≤ x ≤ 0.07. We successfully demonstrated that the crystal’s relatively enhanced d 33 and its excellent temperature stability are originated from phase transition behaviors that were confirmed by the temperature‒dependent dielectric properties and X−ray diffraction (XRD) patterns.