Details

Autor(en) / Beteiligte

• Saltykov, P.
• Fabrichnaya, O.
• Golczewski, J.
• Aldinger, F.

Titel

Thermodynamic modeling of oxidation of Al–Cr–Ni alloys

Ist Teil von

• Journal of alloys and compounds, 2004-11, Vol.381 (1), p.99-113

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2004

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• Morphology changes in the oxide layer during the oxidation process of nickel alloys at 1100 °C was described under simplifying assumptions as a sequence of local phase equilibria. The oxidation behaviour was modeled for binary Ni 60Al 40 and Ni 80Al 20 alloys as well as for a ternary alloy with the composition Al 19.4Cr 19.7Ni 60.9 typically used as a bond coat alloy in thermal barrier coatings for superalloys. The formation of NiAl 2O 4 in equilibrium with Al 2O 3 at the boundary with a bond coat as well as of NiO in equilibrium with NiAl 2O 4 in a top layer on binary Al–Ni alloys was predicted. It was proved that mixed oxides (Al,Cr) 2O 3 as well as mixed spinel phase Ni(Al,Cr) 2O 4 appear with the Al 19.4Cr 19.7Ni 60.9 ternary alloy in bottom and upper zones of thermally grown oxide layer, respectively. The stronger disposition to oxidation of Cr doped alloys compared to binary Al–Ni alloys was established. It was shown that alumina can form only on the surface of β rich grains.