About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
|
Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
|
| Presentation Title |
Evidence for accelerated grain boundary diffusion during ultrafast firing (UHS) of alumina |
| Author(s) |
Zonghao Guo, Richard I. Todd |
| On-Site Speaker (Planned) |
Richard I. Todd |
| Abstract Scope |
Conventional sintering is a slow process but recently densification in only a few seconds has been demonstrated using very rapid heating. One reason for this is simply that the time taken to reach the sintering temperature is greatly reduced by rapid heating. However, detailed analysis of the densification of alumina at different heating rates shows that the sintering itself is also accelerated by rapid heating. This is partly accounted for by microstructural refinement but there remains an increase in sintering rate at a given temperature and density of up to a factor of 20, suggesting an increase in the diffusion rate. This is directly investigated here by adding particles of Cr<sub>2</sub>O<sub>3</sub> to alumina green bodies as a diffusion tracer. The results demonstrate an acceleration of diffusion in the early stages of rapid heating correlating well with the sintering results. Potential reasons for the acceleration are discussed. |