Preparation of Porous Ceramics from Nanocrystalline Zirconia and Their Microstructure

Data are presented on the compaction behavior of nanocrystalline yttria partially stabilized zirconia powder and the effects of compaction pressure, sintering temperature, and sintering time on the microstructure of the resultant ceramics. It is shown that even relatively low (≃50 MPa) compaction pressures lead to the disintegration of powder particles and aggregates. The compaction behavior of the powder points to changes in the densification mechanism: from quasi-liquid sliding of powder particles at the beginning of the process to the breakdown of large microstructural constituents at the end. In the initial stages of sintering, a robust skeleton forms, which plays a key role in determining the pore structure of the ceramic.