Full set of material constants of (Na0.5K0.5)NbO3–BaZrO3–(Bi0.5Li0.5)TiO3 lead-free piezoelectric ceramics at the morphotropic phase boundary

• The full set of material constants of 6BZ/2BLT/92NKN ceramics was obtained.
• Values of d33 and d15 of 6BZ/2BLT/92NKN ceramics were 321 and 602 pC/N, respectively.
• The piezoelectric properties of 6BZ/2BLT/92NKN ceramics are relatively stable against temperature up to 200 °C.
• The main origin of the enhanced piezoelectricity of 6BZ/2BLT/92NKN is the weakened polarization anisotropy.

The perovskite solid solution system of (1−x−y)(Na0.5K0.5)NbO3–xBaZrO3–y(Bi0.5Li0.5)TiO3 (BZ/BLT/NKN) is a new family of lead-free piezoelectric material. Compositions near the morphotropic phase boundary (MPB) (x = 0.06, y = 0.02) have been reported to have good piezoelectric coefficients with the moderate Curie temperature. In this work, the full set of material constants for the MPB composition of BZ/BLT/NKN solid solution was characterized using the resonance method. ε33T, tanδ, d31, d33, d15, Qm and TC are 2496, 0.025, −159 pC/N, 321 pC/N, 602 pC/N, 44 and 256 °C, respectively. The piezoelectric properties are not only superior to those of other (Na,K)NbO3-based ceramics at room temperature, but also relatively stable against temperature up to 200 °C. These results show that BZ/BLT/NKN solid solution is a promising candidate for practical piezoelectric applications in actuating and sensing fields.