NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
nonequilibrium synthesis of nbal3 and nb-al-v alloys by laser cladding. ii - oxidation behaviorIsothermal oxidation behaviors of NbAl3 alloy synthesized by laser cladding were investigated at temperatures between 800 and 1400 C, and the effect of vanadium microalloying on the oxidation of the laser-clad alloy was examined. The oxidation kinetics of the two alloys were monitored using thermal gravimetric weight gain data, and the bulk and surface chemistries were analyzed using XRD and XPS, respectively. It was found that NbAl3 did not form an exclusive layer of protective Al2O3. The oxidation products at 800 C were found to be a mixture of Nb2O5 and Al2O3. At 1200 C, a mixture of NbAlO4, Nb2O5, and Al2O3 formed; and at 1400 C, a mixture of NbAlO4, Al2O3, NbO2, NbO(2.432), and Nb2O5 formed. The addition of V led to a dramatic increase of the oxidation rate, which may be related to the formation of (Nb, V)2O5 and VO2, which grows in preference to protective Al2O3.
Document ID
19920072523
Document Type
Reprint (Version printed in journal)
Authors
Haasch, R. T.
Tewari, S. K.
(Illinois, University Urbana, United States)
Sircar, S.
(Lockheed Engineering and Sciences Co.; NASA, Johnson Space Center Las Cruces, NM, United States)
Loxton, C. M.
Mazumder, J.
(Illinois, University Urbana, United States)
Date Acquired
August 15, 2013
Publication Date
September 1, 1992
Publication Information
Publication: Metallurgical Transactions A - Physical Metallurgy and Materials Science
Volume: 23A
Issue: 9 Se
ISSN: 0360-2133
Subject Category
METALLIC MATERIALS
Funding Number(s)
CONTRACT_GRANT: DE-AC02-76ER-01198
CONTRACT_GRANT: AF-AFOSR-85-0333
Distribution Limits
Public
Copyright
Other