Preparation and properties of 3–1 type PZT ceramics by a self-organization method

In this work, 3–1 type PZT ceramics with unidirectionally aligned channels have been fabricated by ionotropic gelation process of alginate/PZT suspensions. The 3-1 type PZT ceramics with porosity ranging from 36.9% to 60.6% were fabricated by adjusting the initial solid loading (5–25 wt%) of slurries. By incorporating CaO into PZT matrix during the process, the relative permittivity of porous ceramics was reduced, which was beneficial for enhancing the value of hydrostatic figure of merit (HFOM). With regard to the piezoelectric and mechanical properties, due to the combination of highly ordered capillary structure and doping of CaO, 3–1 type PZT ceramics demonstrated excellent performances. As a result, the prepared samples possessed a maximal HFOM value of 7.6 × 10−12 Pa−1 and compressive strength of 125 MPa. The acoustic impedance (Z) of specimens decreased linearly with increasing porosity, making them promising candidates for application to underwater sonar or medical imaging.