Piezoelectric Properties of (Bi0.5Na0.5)TiO3-Based Solid Solution at Large-Amplitude Vibration

Abstract

The high-power piezoelectric characteristics of (Bi0.5Na0.5)TiO3 based solid solution ceramics, x(Bi0.5Na0.5)TiO3-y(Bi0.5Li0.5)TiO3-zBaTiO3 + MnCO3 w wt% [x + y + z = 1, y = 0.04, z = 0.02–0.08, BNLBT4-100z + Mnw], were focused on under large-amplitude vibration in this study. The BNLBT4-100z system has a morphotropic phase boundary (MPB) at approximately z = 0.06, and BNLBT4-2 and BNLBT4-4 exhibited rhombohedral symmetry, whereas BNLBT-4-8 exhibited tetragonal symmetry. The piezoelectric strain constant, d 33, for the MPB composition (z = 0.06) under small-amplitude vibration was the largest (>40 pC/N) among all compositions and the mechanical quality factor, Q m, of the composition with rhombohedral symmetry was higher than those of compositions with other symmetries. The vibration velocity, which was measured using a laser Doppler vibrometer reached 2 m/s for BNLBT4-2+Mn0.4 and BNLBT4-4+Mn0.4 rhombohedral symmetry and BNLBT4-6+Mn0.4 with the MPB, as compared with 1 m/s for BNLBT4-8+Mn0.4 with tetragonal symmetry. These results indicate that BNLKT4-4+Mn0.4 ceramic with rhombohedral symmetry is a promising candidate material for use in lead-free high-power piezoelectric devices.