  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.
