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The effect of zirconium on the isothermal oxidation of nominal Ni-14Cr-24Al alloysThe isothermal oxidation of Ni-14Cr-24Al-xZr-type alloys was performed in still air at 1100, 1150, and 1200 C for times up to 200 hr. The zirconium content of the alloys varied from 0-0.63 atom percent (a/o). The oxidized surfaces were studied by optical microscopy, X-ray diffraction, and scanning electron microscopy. The base alloy was an alumina former with the zirconium-containing alloys also developing some ZrO2. The addition of zirconium above 0.066 a/o increased the rate of weight gain relative to the base alloy. Due to oxide penetratio, the weight gain increased with Zr content; however, the scale thickness did not increase. The Zr did increase the adherence of the oxide, particularly at 1200 C. The delta W/A vs. time data fit the parabolic model of oxidation. The specific diffusion mechanism operative could not be identified by analysis of the calculated activation energies. Measurements of the Al2O3 scale lattice constants yielded the same values for all alloys.
Document ID
19800042295
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Kahn, A. S.
(NASA Lewis Research Center Cleveland, OH, United States)
Lowell, C. E.
(NASA Lewis Research Center Cleveland, OH, United States)
Barrett, C. A.
(NASA Lewis Research Center Cleveland, Ohio, United States)
Date Acquired
August 10, 2013
Publication Date
March 1, 1980
Publication Information
Publication: Electrochemical Society
Subject Category
Metallic Materials
Accession Number
80A26465
Distribution Limits
Public
Copyright
Other

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