Piezoelectric properties of PZT-based ceramic with highly aligned pores

Porous lead zirconate titanate-lead zinc niobate (PZT-PZN) piezoelectric ceramics with a high degree of pore alignment were fabricated using directional freeze casting of a ceramic/camphene slurry. Well-aligned pores were formed as the replica of the camphene dendrites that grew in a preferential orientation, while a high porosity of 90% was achieved by employing a low initial solid loading of 5 vol%. As the orientation angle of the pores to the poling direction was decreased, the hydrostatic piezoelectric properties, such as hydrostatic piezoelectric strain coefficient (d_h), the hydrostatic piezoelectric voltage coefficient (g_h), and the hydrostatic figure of merit, increased significantly. The sample containing pores aligned parallel to the poling direction showed an extremely high HFOM of 161019 × 10 ^-15 Pa^-1, which was ∼1300 times higher than that (124 × 10^-15 Pa^-1) of the dense sample, owing to the presence of aligned pores.