Effect of Cu and Li substitution on the piezoelectric properties of potassium sodium niobate lead-free ceramics

Recently, (K, Na) NbO 3 (KNN) ceramics and, based on KNN, (K,Na,Li) NbO 3 ceramics, (K,Na,Li)(Nb,Ta,Sb)O 3 (LF4) perovskite ceramics were reported to show excellent piezoelectric properties and has been regarded as candidates of lead-free piezoelectric materials. In this study, the effect of CuO addition to Li-modified KNN were investigated. The CuO-doping changed it to "hard" piezoelectric ceramics but the Q m can be improved to above 400 for Li-modified KNN with a high piezoelectric constant d 33 of 100 pC/N.