Good temperature stability and fatigue-free behavior in Sm2O3-modified 0.948(K0.5Na0.5)NbO3–0.052LiSbO3 lead-free piezoelectric ceramics

Abstract The rare-earth oxide Sm 2 O 3 -doped 0.948(K 0.5 Na 0.5 )NbO 3 –0.052LiSbO 3 (abbreviated as KNN-LS5.2) lead-free piezoelectric ceramics were prepared using conventional solid sintering method. The effects of Sm 2 O 3 on the phase structure, electrical properties, temperature stability and fatigue behavior of KNN-LS5.2 ceramics were systematically studied. Results showed that Sm 2 O 3 substitution into KNN-LS5.2 induced a phase transition from coexistence of orthorhombic and tetragonal phase to a pseudocubic phase with a normal-relaxor ferroelectric transformation, and correspondingly shifted the polymorphic phase transition (PPT) below room temperature. Accordingly, the temperature stability and fatigue behavior of the modified ceramics were significantly improved. It was found that the KNN-LS5.2 ceramics with 0.6 mol% Sm 2 O 3 addition exhibited nearly temperature independent properties and fatigue-free behavior, together with its good electrical properties ( d 33 * = 167 pm/V, d 33 = 120 pC/N, k p = 33%, Q m = 101, ϵ r = 1326, tan δ = 4.6%). The results suggest that this material should be an attractive lead-free material for piezoelectric applications.