Abstract
Microstructural evolution induced by isothermal exposure at 1100°C in a platinum aluminide coating was investigated. Specimens of CMSX-4 alloy have been platinum aluminised to give a single phase (Ni,Pt)Al coating. Coated alloys were exposed in an oxidising environment for 188, 350, 750 and 1500 hours at a temperature of 1100°C. After isothermal oxidation of the single phase (Ni,Pt)Al coatings the surface is shown to progressively roughen. The compositional development assisted by chemical diffusion during isothermal oxidation at 1100°C has been related to the transformation of the coating from its original ß-NiAl (B2) structure to a Ni-rich (L10) martensite γ. The transformation took place due to aluminium depletion in the coating from the formation of the Al2O3 scale and interdiffusion between the coating and alloy substrate. The effects of phase changes on coating surface character are considered.
| Original language | English |
|---|---|
| Pages (from-to) | 343-350 |
| Number of pages | 8 |
| Journal | Materials Science Forum |
| Volume | 461-464 |
| Issue number | I |
| Publication status | Published - 2004 |
| Event | Proceedings of the 6th International Symposium on High Temperature Corrosion and Protection of Materials - Les Embiez, France Duration: 16 May 2004 → 21 May 2004 |
Keywords
- Aluminium depletion
- CMSX-4 alloy
- Interdiffusion
- Martensitic transformation
- Platinum aluminide