In situ study of the initial stages of oxidation of alloy u-6wt.% nb with angle resolved x-ray photoelectron spectroscopy (ARXPS)

Embong, Zaidi and Younes, Charles M. and Scott, Thomas B. and Allen, Geoffery C. (2009) In situ study of the initial stages of oxidation of alloy u-6wt.% nb with angle resolved x-ray photoelectron spectroscopy (ARXPS). Journal of Science and Technology, 1 (1). pp. 43-55. ISSN 1985-8809

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Abstract

In this work the initial stages of oxidation of a uranium-base alloy (U - 6 wt.% Nb) during exposure to a UHV environment consisting primarily of H2O, CO and CO2 have been studied using the specific surface analysis technique of angled resolved X-ray photoelectron spectroscopy (ARXPS). Examination of the sputter cleaned surface of the alloy has been performed at different take-off angles varying between 0° and 60° prior to and after a prolonged exposure to the UHV atmosphere for approximately 2 hours. The photoelectron spectra recorded for U 4f, Nb 3d and O 1s indicated that the adsorption and dissociation of H2O, CO and CO2 on the alloy surface first leads to the formation of UO2 intermixed with NbO. Other oxides including NbO2 and Nb2O5 along with hydroxyl compounds were clearly detected after exposure times exceeding one hour (360 L). The formation of a critical density of Nb2O5 at the metal-oxide interface is suggested to play a key role in preventing the diffusion of ionic species such as O- and OH– into the oxide-metal interface region, thus conferring a much higher resistance to oxidation and corrosion on the alloy, as compared with that of the unalloyed uranium metal.

Item Type:Article
Uncontrolled Keywords:Angle Resolved XPS (ARXPS); oxidation; U - 6 Wt.% Nb alloy
Subjects:Q Science > QD Chemistry
ID Code:546
Deposited By:Nurhafiza Hamzah
Deposited On:20 Apr 2011 14:15
Last Modified:29 Apr 2011 14:41

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