Characterisation of PZTs Non-Linear Behaviour for High-Power Systems

Lead zirconate titanate (PZT) piezoceramics exhibit non-linear behaviour when large electric fields are applied. This causes the material properties to change through heating and increased mechanical and electrical losses. These may contribute to unexpected device behaviour and ultimately to failure. It is therefore of fundamental importance to characterise piezoelectric materials under high-power driving conditions for applications requiring large electric field. Ten different PZT compositions were investigated in the work presented here. Length-thickness-extensional (LTE) d(31)-mode plates were characterized under small signal excitation through electrical impedance spectroscopy, with curve fitting software (PRAP, TASI, Ontario, CAN) used to obtain the material properties. Subsequently, a high-power characterisation system was assembled, including a signal generator (33210A, Agilent, CA, USA), power amplifier (2100L, E & I, NY, USA), AC current probe (P6022, Tektronix, ORE, USA), differential voltage probe (GE8115, GE, GER), and DAQ (USB6346, National Instruments, TEX, USA). Bespoke software was used to acquire the electrical impedance through fast sine wave frequency sweeps in the range 1 - 200 V-pp. This enabled evaluation of material properties with large electrical excitation. Additionally, a 1-D laser Doppler vibrometer (OFV 303, Polytec, GER), was integrated into the set-up to determine the transient vibrational response and determine the mechanical quality factor.