Preparation of porous PZT with high connectivity using capsule-free O2-HIP and their dielectric properties

Abstract

Abstract The processing of porous PZT ceramics with high connectivity was investigated using capsule-free O2-HIP technology. PreHIPed porous PZT bodies were prepared by pressureless-sintering of green compacts with various amounts of spherical PMMA particles, followed by hot-isostatically pressed at 1100°C and 200 MPa for 1 h in 5% O2/Ar mixture gas atmosphere. Little densification of porous PZT sintered bodies occurred by capsule-free O2-HIP treatment, resulting in the formation of well-developed neck growth between PZT grains. They exhibited a homogeneous microstructure with a bimodal pore distribution consisting of both several μm and 50 ∼ 80 μm pore sizes. The HIPed porous PZT ceramics have a larger permittivity and a smaller depolarizing factor about a half rather than those of pressureless-sintered porous PZT bodies, suggesting that the HIPed PZT has a higher connectivity. Piezoelectric g33 constant-porosity relations were also described.