Abstract
Alumina scales formed during cyclic oxidation at 1200°C on three Y2O3-Al2O3-dispersed alloys: Ni3Al, β-NiAl, and FeCrAl (Inco alloy MA956) were characterized. In each case, the Y2O3 dispersion improved the α-Al2O3 scale adhesion, but in the case of Ni3Al, an external Ni-rich oxide spalled and regrew, indicating a less-adherent scale. A scanning-transmission electron microscope (STEM) analysis of the scale near the metal-scale interface revealed that the scale formed an ODS FeCrAl showed no base metal-oxide formation. However, the scale formed on ODS Ni3Al showed evidence of cracking and Ni-rich oxides were observed. The microstructures and mechanisms discussed may be relevant to a thermal-barrier coating with an Al-depleted aluminide bond coat nearing failure.
Original language | English |
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Pages (from-to) | 119-145 |
Number of pages | 27 |
Journal | Oxidation of Metals |
Volume | 56 |
Issue number | 1-2 |
DOIs | |
State | Published - 2001 |
Keywords
- Adhesion
- AlO
- High-temperature oxidation
- ODS alloys
- Reactive-element effect