Flexible Al/PZT/Al composite for piezoelectric applications

Flexible lead zirconate titanate (PZT) thin films have been developed by a chemical process (CSD), using aluminium foil as substrate, in view of optimizing their piezoelectric properties. Due to the mechanical properties of the aluminium foil (16 μm thick, 69 GPa as for Young's modulus), original forms have been obtained because such a thin film is easily cuttable, and the conformable. Despite the mechanical mismatch between brittle PZT and its flexible substrate, hysteresis loop obtained during the P-E measurements has demonstrated high remnant polarization (26 μC/cm
²
that augurs exploitable macroscopic piezoelectric behavior. Al/PZT/Al cantilever beam has been realized and very high deflections (in the centimeter range) have been observed when subjected to low applied voltages (up to 10 V). Besides, the sensitivity of a 0.8 cm long Al/PZT/Al cantilever to acoustic waves has been measured, yielding a resonance frequency of 220 Hz and a quality factor of 47, thanks to great flexibility of the thin aluminium substrate. At last, waterproof multilayer composite has been realized by encapsulation of the beam using polyethylene terephthalate (PET). The so formed alga has been used to sense the low frequency (~1 Hz) of swell generated in an experimental basin.