Properties of Quasi 1-3 Piezoelectric PZT-epoxy Composites Obtained by Dielectrophoresis

Abstract

The dielectric and piezoelectric properties of piezoelectric particle—epoxy polymer composites structured into 1-3 composites via dielectrophoresis during curing are reported. The dielectrophoretic alignment induces a textured microstructure in the composite, with particles forming chains in the direction of the electric field. The particles form a quasi-1-3 connectivity structure which influences the dielectric and piezoelectric properties of the composite in this direction. The maximum g₃₃ of the Pb(Zr,Ti)O₃—epoxy system that was investigated was increased compared to the maximum g₃₃ for a 0-3 composite of the same system. Furthermore, these maximum values are achieved at a Pb(Zr,Ti)O₃ volume fraction of 0.1, which is much lower than in conventional 0-3 composites. The effect of the amplitude of the applied electric field at high volume fractions of filler on the dielectric and piezoelectric properties of the composites is discussed. Additionally, the polarisation behavior of the composites at high electric fields is discussed. The experimental data are quantitatively described by a new microstructure-based model.

Keywords:

• Piezoelectric composites
• dielectrophoresis
• electric field structuring

Acknowledgments

This work was financially supported by the Smartmix funding program (grant SMVA0607), as part of the program “Smart systems based on integrated Piezo”. The authors are grateful to Morgan Electro Ceramics (Ruabon, United Kingdom) for providing the PZT powder and to Indu Babu and prof. Bert de With (SMG group, Eindhoven University of technology), for the use of their Berlincourt d₃₃ meter.