| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
Deducing Surface-scale Chemical Conditions from Equilibrium Nanoparticle Shapes |
| Author(s) |
Mujan N. Seif, T. John Balk, Matthew J. Beck |
| On-Site Speaker (Planned) |
Mujan N. Seif |
| Abstract Scope |
As applications of nanoparticles continue to expand, precise control of their functional surfaces becomes increasingly valuable. While the macroscopic or average environmental chemical conditions in which nanoparticles are equilibrated can be controlled and the resulting shapes observed via SEM, the details of local, nanoscale conditions present during particle evolution remain unclear and, in some cases, prohibitively difficult to establish. Here, we use density functional [perturbation] theory to build a computational thermodynamic framework by which we “reverse engineer” nanoscale chemical conditions and map them back to controllable macroscopic environmental conditions. The case study presented here highlights scandate thermionic cathodes—next-generation electron emitters repeatedly observed to be composed of W nanoparticles with a highly-faceted, unique characteristic shape. We demonstrate that the chemical composition of each facet can be predicted as a function of temperature and oxygen availability and use these results to hypothesize the origin of scandate cathodes’ exceptional electron emission properties. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Electronic Materials, Phase Transformations |