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Record Details

Record 11 of 485
Some TEM observations of Al2O3 scales formed on NiCrAl alloys
Author and Affiliation:
Smialek, J.(NASA Lewis Research Center, Cleveland, Ohio, United States)
Gibala, R.(NASA Lewis Research Center, Case Western Reserve University)
Abstract: The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids have been observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. It was postulated that the voids resulted from an excess number of oxygen vacancies near the oxide-metal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidations of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al,Cr)2O3 and Ni(Al,Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationships between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.
Publication Date: Jul 01, 1979
Document ID:
19800028901
(Acquired Nov 30, 1995)
Accession Number: 80A13071
Subject Category: METALLIC MATERIALS
Document Type: Conference Paper
Publisher Information: United States
Meeting Information: Gordon Research Conference on Corrosion; July 23-27, 1979; New London, NH
Financial Sponsor: NASA; United States
Organization Source: NASA Lewis Research Center; Cleveland, OH, United States
Case Western Reserve Univ.; Cleveland, OH, United States
Description: 32p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ALUMINUM OXIDES; CRYSTAL GROWTH; ELECTRON MICROSCOPY; MICROSTRUCTURE; NICKEL ALLOYS; SCALE (CORROSION); TRANSMISSION ELECTRON MICROSCOPY; ALUMINUM ALLOYS; CHROMIUM ALLOYS; METAL OXIDES; YTTRIUM; ZIRCONIUM
Imprint And Other Notes: Gordon Research Conference on Corrosion, New London, N.H., July 23-27, 1979, Paper. 32 p.
Availability Source: Other Sources
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