| About this Abstract |
| Meeting |
Materials Science & Technology 2009
|
| Symposium
|
Characterization and Modeling of Ceramic-Ceramic and Metal-Ceramic Interfaces
|
| Presentation Title |
**Ab Initio Modeling of Ba-O-Sc on W Cathode Materials (Previously scheduled in the Discovery and Optimization of Materials through Computational Design symposium on Wednesday at 10:00 AM) |
| Author(s) |
Vasilios Vlahos, Dane Morgan, John H. Booske |
| On-Site Speaker (Planned) |
Dane Morgan |
| Abstract Scope |
Microwave, x-ray, and radio frequency radiation sources require a cathode emitting electrons into vacuum. Good electron emitters can be obtained by lowering the work function of materials through dipole surface coatings. Ba-O on W is used in traditional B-type cathodes, and Ba-O-Sc coatings may play a role in the promising new class of scandate cathodes. Ab initio modeling is used to explore the surface structure, stability, and work function of Ba-Sc-O on W coatings. The overall accuracy of the approach is assessed and resolutions to some previous ab initio and experimental discrepancies are proposed. We demonstrate that measured B-type cathode work functions are consistent with a lower coverage than previously expected and a dynamic stabilization of dipole surface structures very far from equilibrium. We also proposed a low work function Ba-Sc-O surface structures that may play a role in new scandate cathode materials. |
| Proceedings Inclusion? |
Undecided |