Sulfur Segregation at Al2O3/γ-Νi + γ′-Ni3Al Interfaces: Effects of Pt, Cr and Hf Additions
| Autor: | T. Izumi, Brian Gleeson, Peggy Y. Hou |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Materials science
Metallurgy Alloy Metals and Alloys Analytical chemistry Intermetallic Oxide chemistry.chemical_element engineering.material Microstructure Sulfur Inorganic Chemistry chemistry.chemical_compound chemistry visual_art Materials Chemistry Aluminium alloy visual_art.visual_art_medium engineering Platinum Nickel aluminide |
| Zdroj: | Oxidation of Metals. 72:109-124 |
| ISSN: | 1573-4889 0030-770X |
| DOI: | 10.1007/s11085-009-9149-y |
| Popis: | The interfacial chemistry that developed as a result Al2O3-scale growth on γ-Νi + γ′-Ni3Al alloys at 1150 °C was studied using scanning Auger microscopy after the oxide layer was scratched to spall under ultra-high vacuum. The extent of scale spallation was used to evaluate semi-quantitatively the interfacial strength. The alloys investigated were primarily γ′ in structure, containing 22 at.% Al plus further additions of Pt, Cr and/or Hf. In the case of the binary γ + γ′ alloy, it was found that a sub-monolayer of sulfur segregated at the alloy/scale interface. Platinum reduced and hafnium eliminated sulfur segregation, but chromium enhanced it through Cr–S co-segregation, even on Pt- and Hf-containing alloys. Platinum also segregated slightly at the alloy/scale interface. The interface strength was a strong function of the sulfur content. Beyond the effect of eliminating S segregation, Pt and Hf both showed additional beneficial effects on alumina scale adhesion. |
| Databáze: | OpenAIRE |
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