Piezoelectric and mechanical properties of CaO reinforced porous PZT ceramics with one-dimensional pore channels

The formation of capillaries in sodium alginate gels is a dissipative process driven by unidirectional diffusion of divalent cations into sodium alginate sols. In the present work, we have prepared 3-1 type porous lead zirconate titanate (PZT) ceramics with oxides (CaO) being doped on a molecular level from the dissipative process by incorporating PZT particles into the sodium alginate gel matrix. By varying the concentration of cation solutions (CaCl2) from 0.5 mol/L to 2.5 mol/L, both the microstructure, doping amount of oxides (CaO) and crystalline phase of the porous PZT ceramics were tailored. Accordingly, increase in the concentration of Ca2+ has led to a reduction in the relative permittivity (epsilon(r)) first, and then an increase, while the piezoelectric coefficient (d(33) and d(31)) demonstrated an opposite variation tendency. The prepared samples possessed a maximal HFOM value of 4755x10(-15) Pa-1 when the concentration of Ca2+ was 1.0 mol/L. Addition of CaO was found to improve the compressive strength of porous PZT ceramics, which was preferential to promoting the stability and reliability for application.