Low‐Temperature Sintering and Piezoelectric Properties of (Na _0.5 K _0.5 )NbO ₃ Lead‐Free Piezoelectric Ceramics

Abstract

(Na 0.5 K 0.5 )NbO 3 (NKN) ceramic with 1.5 mol% CuO added (NKNC) was well sintered even at a low temperature of 900°C with the addition of ZnO. Most of the ZnO reacted with the CuO and formed the liquid phase that assisted the densification of the specimens at 900°C. A few Zn 2+ ions entered the matrix of the specimens and increased the coercive field ( E c ) and Q m values of the specimens. High‐piezoelectric properties of k p =0.37, Q m =755, and ɛ 3 T /ɛ 0 =327 were obtained from the NKNC ceramics containing 1.0 mol% ZnO sintered at 900°C for 2 h.