Surface composition of Cu-Li alloys: The influence of oxygen on bombardment and segration effects

Cu-Li alloys are considered as first-wall material in fusion devices because they bear the possibility of reducing the sputtering of a high-Z material (Cu) due to a segregated surface Layer of Li. Reduced Cu sputtering rates have indeed been found under certain conditions. In this work the surface c...

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Bibliographic Details
Published inJournal of nuclear materials Vol. 162; pp. 920 - 923
Main Authors Baretzky, B., Taglauer, E., Möller, W., Schorn, R.P.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.04.1989
Subjects
erosion
segregation
sputtering
erosion
sputtering
segregation
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Summary:Cu-Li alloys are considered as first-wall material in fusion devices because they bear the possibility of reducing the sputtering of a high-Z material (Cu) due to a segregated surface Layer of Li. Reduced Cu sputtering rates have indeed been found under certain conditions. In this work the surface compositions of alloys ranging from 6 to 24 at% in Li content were analyzed using ion scattering spectroscopy (ISS) and Auger electron spectroscopy (AES). The varying information depths of both techniques allow the analysis of the near surface depth distribution of Li. Already at room temperature Li segregation to the surface is observed, the segregation rate depending on the bulk composition. It is influenced by the bulk oxygen impurity concentration, which was detected by nuclear reaction analysis. Under ion bombardment the Li surface concentration is reduced, the steady state composition can be described by the balance between sputtering and segregation. A change from He + to Ar + ions results in increased Li depletion as expected from the increased sputtering yield. Some consequences for the usefulness of these alloys for first-wall material are discussed.
ISSN:0022-3115
1873-4820
DOI:10.1016/0022-3115(89)90386-3