| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Powder and Ceramic Materials Science
|
| Presentation Title |
High Densification Rates (10-3 s-1) in Nanocrystalline Oxides by CAPAD Processing: Effects of Water Absorption and Grain Size |
| Author(s) |
Darren Dewitt, Yasuhiro Kodera, Javier E Garay |
| On-Site Speaker (Planned) |
Darren Dewitt |
| Abstract Scope |
The effects of grain size and water on the densification of oxide powders have long been recognized, but their effects on densification rates have not been adequately studied. Here, we measured the real-time densification rates of MgO using the current-activated, pressure-assisted densification (CAPAD) technique. The rates of samples densified from powders with grain sizes ~40nm are similar to those measured previously for other nanopowders, while those from 29nm powder are higher. Exposure to a humid environment increases the densification rates and allows densification at lower temperatures. The densification rate curves of samples with absorbed water display two peaks implying two controlling mechanisms, while the dry samples display one. We attribute lower temperature densification to Mg(OH)2-MgO conversion and the higher to diffusion-controlled densification. Recent work involving the densification of MgO+Al2O3 nanopowders in CAPAD will also be discussed - correlating densification rates with various mechanisms, including the phase evolution of MgAl2O4. |
| Proceedings Inclusion? |
Planned: |