High strain in (K0.40Na0.60)(Nb0.955Sb0.045)O3–Bi0.50Na0.50ZrO3lead-free ceramics with large piezoelectricity

We have attained both large piezoelectricity and high strain in (1 − x)(K0.40Na0.60)(Nb0.955Sb0.045)O3–xBi0.50Na0.50ZrO3 [(1 − x)KNNS–xBNZ] lead-free ceramics by forming a rhombohedral (R) and tetragonal (T) phase boundary. The ceramics with 0.035 < x < 0.05 possess R and T phases' coexistence. A large d33 value of ∼450 pC N−1 has been attained when the x value reached 0.04 owing to the involved R–T phase boundary, which is higher with respect to d33 ∼ 416 pC N−1 of textured (K,Na,Li)(Nb,Ta,Sb)O3 ceramics reported by Saito et al. [Nature, 2004, 432, 84]. In addition, it is worth noting that such a ceramic simultaneously possesses a high electric field-induced strain (0.2%) under a low driving electric field of ∼2 kV mm−1, and its Smax/Emax value is equal to be 1071 pm V−1. As a result, we can believe that the (1 − x)KNNS–xBNZ ceramics will become one of the promising material systems in the practical applications of electrical devices.