Temperature stability of lead-free piezoelectric ceramics of perovskite Bi0.5Na0.5TiO3 and K0.5Na0.5NbO3 families

From the viewpoint of application, the temperature stability of the electrical properties of the lead-free piezoelectric ceramics is very important. Therefore, it is important to study the temperature stability of the electrical properties of perovskite Bi_0.5Na{0.5}TiO₃ (BNT)- and K_0.5Na_0.5NbO₃ (KNN)-based (Bi_0.47Na_0.47)Ba_0.06TiO₃ (BNBT6) and (K_0.49Na_0.49)Li_0.02Nb_0.95Sb_0.05O₃ (KNLNS2-5) were selected, and the temperature stability of the dielectric, piezoelectric, and ferroelectric properties of the two kinds of ceramics were compared from the point of view of the application of the ceramics. It was found that the piezoelectric properties of KNLNS2-5 ceramics are much more stable in the orthorhombic phase than in the tetragonal phase. This is an important clue to obtain excellent piezoelectric properties along with good temperature stability for KNN-based ceramics.