Large-amplitude piezoelectric properties of KNbO3-based lead-free ferroelectric ceramics

Abstract

High-power piezoelectric characteristics of Mn- doped KNbO3 (KN + MnCO3 at x wt%, x = 0 to 0.8 wt%, KN-Mnx) ceramics are reported for the first time in this paper. The mechanical quality factor Qm of KN-Mnx ceramics at small-amplitude vibration increased with the Mn content, and the Qm of KN-Mn0.8 ceramic reached about 820. The maximum vibration speed vo-p, about 2.3 ms, was obtained for KN-Mn0.8 with Q m = 820. Qm for large-amplitude vibration in KN-Mn0.8 and Pb(Zr, Ti)O3 (PZT)-based ceramics (N6) decreased with increasing vo-p. Qm of KN-Mn0.8 was smaller than that of N6 for small-amplitude vibration. However, for large-amplitude vibration at which vo-p > 0.6 m/s, the Qm value of KN-Mn0.8 was larger than that of N6. These results indicate that KN-based lead-free piezoelectric ceramics possess superior mechanical stability for large-amplitude vibration. This is a very good sign for high-power piezoelectric applications. © 2013 Wiley Periodicals, Inc.