| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Phase Transformations and Microstructural Evolution
|
| Presentation Title |
(S)TEM Investigation of a Passivating Alumina Layer Formed During Air Annealing of CVD-Grown Hf(1-x)AlxB2 Coatings |
| Author(s) |
Carly J. Romnes, Kinsey Canova, Zoë Tucker, Zhejun Zhang, John R. Abelson, Jessica Krogstad |
| On-Site Speaker (Planned) |
Carly J. Romnes |
| Abstract Scope |
Transition metal diboride protective coatings are of interest in automotive, aerospace, and manufacturing industries due to the potential to improve hardness, chemical inertness, and increase wear resistance. Currently, use of diboride coatings is limited due to the onset of oxidation above 700°C. We report an innovative, low temperature, chemical vapor deposition process that results in a metal diboride film with improved oxidation resistance and is well-adherent and conformal. The coatings consist of mixed-metal alloy diborides in which the second metal is an effective oxide former. During annealing, a dense and protective surface oxide evolves to afford oxidation resistance, while the bulk transforms into a nanocrystalline phase. To better understand the annealing behavior, these coatings were investigated at various time stages during isothermal annealing using transmission electron microscopy (TEM), scanning TEM, and energy dispersive x-ray spectroscopy. We report key insights on the relationship between microstructural evolution and oxidation resistance. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |