CORROSION · 1976 · 45 citations · 7 references
Natural SciencesMaterials EngineeringMaterials ScienceCorrosion ScienceMetallic MaterialsMetallurgyAlloysCoatingsCorrosion ResistanceCorrosion-resistant MaterialsMetalsNickel-based SuperalloysAluminide CoatingsCorrosion-resistant AlloysHot CorrosionHot Corrosion ResistanceNickel AlloysNickel-based AlloysPrimary Constituent ElementsSuperalloys
Hot corrosion behavior of pure and alloyed γ′-Ni3Al (the major strengthening phase in Ni-base superalloys) and β-NiAl (the primary constituent of aluminide coatings) phases at 1600 F was investigated using burner rig tests. The results indicated that for exposure times greater than 100 hours, pure β-NiAl was more corrosion-resistant than γ′-Ni3Al; for shorter times, the kinetics were found to be comparable. Corrosion of γ′-Ni3Al was thus characterized by an incubation period of the order of 100 hours. Chromium was found to improve the hot corrosion resistance of NiAl considerably. Addition of Y to Cr-doped β-NiAl caused only modest additional improvements in corrosion resistance. In the case of γ′-Ni3Al, Ta and Cr were found to markedly improve short-term hot corrosion performance, W appeared to be innocuous, whereas Ti definitely reduced its corrosion resistance.
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