(K0.5Na0.5)NbO3 based lead free piezoelectrics with expanded temperature usage range

摘要

Lead free materials 0.95(K0.5Na0.5)NbO3-0.05LiSbO3 modified by CaTiO3 (CT) (1??3wt%) have been synthesized by conventional sintering. All samples exhibited pure perovskite phase with a tetragonal structure at room temperature. The Curie temperature was found to decrease with increasing CT addition in KNN-LS ceramics, while the orthorhombic to tetragaonl polymorphic phase transition was found to shift further downward from room temperature to lower than ??50?°C, expanding the temperature usage range. The piezoelectric coefficient d31 and electroemchanical coupling factor k31 for CT (1wt%) modified KNN-LS materials were found to be on the order of ??90pC/N and ??28.5% at room temperature, respectively, comparable to those values of pure KNN-LS. Together with its broadened temperature usage range, makes the CT modified materials promising candidates for sensor and transducer applications.