PROCESSING OF POROUS 3-3 PZT CERAMICS USING CAPSULE-FREE O2-HIP

The processing of porous 3-3 type PZT ceramics was investigated using capsule-free O2-HIP. Porous PZT sintered bodies with relative density of about 50-80% were prepared from the green compacts with various amounts of spherical Polymethylmethacrylate (PMMA) particles. They exhibited a homogeneous microstructure with a bimodal distribution consisting of small pores of several mu-m and large pores of 50-80-mu-m in the PZT matrix. Little densification of porous PZT sintered bodies occurred after capsule-free O2-HIP treatment, and the neck growth of PZT interparticles was well developed, leading to the formation of porous 3-3 type PZT ceramics with a higher connectivity. The HIPed porous ceramics possessed a large permittivity and a small depolarizing factor of about half those of normally sintered porous PZT bodies.