| About this Abstract |
| Meeting |
2021 TMS Annual Meeting & Exhibition
|
| Symposium
|
Ni-Co 2021: The 5th International Symposium on Nickel and Cobalt
|
| Presentation Title |
Effect of Fluorine on the High Temperature Oxidation Behavior of Nickel-based Alloys |
| Author(s) |
Alexander G. Donchev, Mathias Galetz |
| On-Site Speaker (Planned) |
Alexander G. Donchev |
| Abstract Scope |
The Al content of conventional Ni-based alloys usually is not enough to form a protective outer alumina layer. Instead a chromia scale develops during high temperature exposure in oxidizing environments with local internal alumina formation. This chromia layer exhibits some disadvantages, e.g. rather high growth kinetics, permeability to nitrogen or Cr oxide evaporation above 900°C. On the other hand, alumina does not show such disadvantages. In a new attempt fluorine is applied on the surface of several conventional Ni-alloys to promote the formation of a protective alpha-Al2O3 layer via the so-called fluorine effect. The almost exclusive formation of gaseous aluminum fluorides in the surface zone of the components and their subsequent transformation towards aluminum oxide stimulates the formation of an outer alumina layer during high temperature service. Results of high temperature exposure tests of untreated and fluorinated specimens of several technical Ni alloys will be presented and discussed. |
| Proceedings Inclusion? |
Planned: |