High piezoelectric sensitivity and hydrostatic figures of merit in unidirectional porous ferroelectric ceramics fabricated by freeze casting

TL;DR

This study demonstrates that unidirectional porous PZT ceramics fabricated via freeze casting exhibit enhanced piezoelectric sensitivity and hydrostatic figures of merit, making them promising for sensor and hydrophone applications.

Contribution

It introduces a freeze casting method to produce aligned porous PZT ceramics with improved piezoelectric and hydrostatic properties, and shows how polarization orientation affects performance.

Findings

Aligned porosity enhances piezoelectric constants.

Parallel polarization yields higher hydrostatic figures of merit.

Porous PZT outperforms dense ceramics in sensing applications.

Abstract

High performance lead zirconate titanate (PZT) ceramics with aligned porosity for sensing applications were fabricated by an ice-templating method. To demonstrate the enhanced properties of these materials and their potential for sensor and hydrophone applications, the piezoelectric voltage constants hydrostatic parameters and AC conductivity as a function of the porosity in directions both parallel and perpendicular to the freezing temperature gradient were studied. As the porosity level was increased, PZT poled parallel to the freezing direction exhibited the highest coefficients, and hydrostatic figures of merit compared to the dense and PZT poled perpendicular to the freezing direction. This work demonstrates that piezoelectric ceramics produced with aligned pores by freeze casting are a promising candidate for a range of sensor applications and the polarisation orientation relative to the freezing direction can be used to tailor the microstructure and optimise sensitivity for sensor and hydrostatic transducer applications.