Large d33 in (K,Na)(Nb,Ta,Sb)O3-(Bi,Na,K)ZrO3 lead-free ceramics

Abstract

To protect the environment and human health, it is necessary to develop high-performance lead-free piezoceramics to replace the lead-based ones in some electronic devices. Here we report first a large piezoelectricity in (K,Na)NbO₃-based lead-free piezoceramics prepared by the conventional solid-state method. The rhombohedral–tetragonal phase boundary is observed in the ceramics with a composition of 0.04 ≤ x ≤ 0.06. Those ceramics with 0.01 ≤ x ≤ 0.06 possess a good comprehensive performance of d₃₃ (380–460 pC N⁻¹) and T_C (170–287 °C). Moreover importantly, a peak d₃₃ of ∼460 pC N⁻¹ is shown in the ceramic with x = 0.04, which is superior to all other reported results of KNN-based ceramics, including the reported results by Saito et al. (Nature, 2004, 432, 84). We believe that such a material system is a very promising candidate for potassium–sodium niobate piezoceramics.