Abstract
Oxidation mechanisms in polycrystalline Co–Ni–Cr–Al–W–Ta alloys were investigated using 16O/18O isotopic tracer analysis in the focused ion-beam secondary ion mass spectrometer (FIB-SIMS). It was found that Al additions favour the formation of a continuous alumina-rich layer, that Cr indirectly improved oxidation resistance and that increasing the Co fraction resulted in poorer oxidation performance. In the alloy containing 15 at.% Cr and 10 at.% Al, the outer scale formed after 200 h oxidation at 800 °C comprised oxides less than 1 μm thick. It is concluded that protective oxide scales can be formed in Co–Ni base superalloys.
Original language | English |
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Pages (from-to) | 44-52 |
Number of pages | 9 |
Journal | Corrosion Science |
Volume | 116 |
Early online date | 23 Dec 2016 |
DOIs | |
Publication status | Published - 15 Feb 2017 |
Keywords
- oxidation
- SIMS
- STEM
- superalloys