Densification Behaviors in the Early Stage of Spark Plasma Sintering of 3Y-TZP Nanoceramics

摘要

The early-stage sintering behaviors of 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3 Y-TZP) ceramics during spark plasma sintering (SPS) was investigated using different pressure and heating regimes. It was found that dependent neither on pressure value (20-100 MPa) nor heating rates higher than 50°C/min, the maximum densification rate had always been observed at rather similar -78% of theoretical density (TD), where the grain growth was rather moderate. A novel intensive-particle-rearrangement mechanism was proposed to dominate the rapid densification of early-stage SPS process, by which yielded the considerable faster densification rate than those achievable by diffusion-related processes. Present findings showed the possibility of particle rearrangement in high density compacts and the effects of classic particle rearrangement should be re-evaluated in nanoceramic sintering.