NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
O-18 tracer studies of Al2O3 scale formation on NiCrAl alloysDiffusion processes in Al2O3 scales formed on NiCrAl + Zr alloys were studied by the proton activation technique employing the O-18 isotope as a tracer. The O-18 profiles identified a zone of oxide penetration beneath the external scale. Both this subscale formation and the outer Al2O3 scale thickness were shown by this technique to increase with Zr content in the alloy. Estimated kp's from scale thicknesses were in agreement with gravimetric measurements for various Zr levels. Alternate exposures in O-16 and O-18 revealed that oxygen inward transport was the primary growth mechanism. A qualitative analysis of these O-18 profiles indicated that the oxygen transport was primarily via short-circuit paths, such as grain boundaries.
Document ID
19830029031
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Reddy, K. P. R.
(Case Western Reserve Univ. Cleveland, OH, United States)
Cooper, A. R.
(Case Western Reserve University Cleveland, OH, United States)
Smialek, J. L.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 11, 2013
Publication Date
June 1, 1982
Publication Information
Publication: Oxidation of Metals
Volume: 17
Subject Category
Metallic Materials
Accession Number
83A10249
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available