AVS 52nd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP28
Photoemission and Secondary Ion Mass Spectrometry Study of Uranium Passivation by Ion Implantation

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Surface Science Poster Session
Presenter: A.J. Nelson, Lawrence Livermore National Laboratory
Authors: A.J. Nelson, Lawrence Livermore National Laboratory
T.E. Felter, Lawrence Livermore National Laboratory
K.J. Wu, Lawrence Livermore National Laboratory
C. Evans, Lawrence Livermore National Laboratory
J.L. Ferreira, Lawrence Livermore National Laboratory
W.J. Siekhaus, Lawrence Livermore National Laboratory
W. McLean, Lawrence Livermore National Laboratory
Correspondent: Click to Email
Implantation of C@super+@ ions into U@super238@ produces a physically and chemically modified surface layer that prevents further air oxidation and corrosion. X-ray photoelectron spectroscopy and secondary ion mass spectrometry were used to investigate the surface chemistry and electronic structure of this C@super+@ ion implanted polycrystalline uranium compared to an unimplanted region of the sample, both regions exposed to air for more than a year. In addition, scanning electron microscopy was used to examine and compare the surface morphology of the two regions. High-resolution U 4f, O 1s and C 1s core-level and valence band spectra clearly indicate carbide formation in the modified surface layer. The time-of-flight secondary ion mass spectrometry depth profiling results reveal an approximately 200 nm thick UC layer with little or no residual oxidation at the carbide layer/U metal interface and a small amount of oxidation at the surface. This work was performed under the auspices of the U.S. Dept. of Energy by the University of California Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.