BiFeO3-modified (K, Na, Li) (Nb, Sb)O3 lead free ceramics with high Curie temperature

(K,Na)NbO3-based lead-free piezoelectric ceramics with high properties have attracted great interest because of the increasing environmental concerns. In this work, a potential lead-free candidate (1-x) (K0.45Na0.55)0.96Li0.04Nb1-ySbyO3-xBiFeO3 (KNLNSy-xBF) with rhombohedral-tetragonal (R-T) phase boundary was systematically investigated. Benefiting from the R-T phase boundary, the enhanced electrical properties (e.g., d33∼365 pC/N, kp∼0.503, εr ∼1689 and tan δ∼0.03) as well as high Curie temperature (Tc∼370 °C) were obtained in the composition of y = 0.035, almost comparable to that of PZT5A (Navy II) piezoelectric ceramics. In addition, a good thermal stability of d33 (Ta = 365 °C, d33 ≥ 280 pC/N) was found in the ceramics with y = 0.035. We believe that the BiFeO3-modified (K, Na, Li) (Nb, Sb)O3 lead-free ceramics with high Curie temperature is a promising candidate for piezoelectric devices.