CEELS as a Probe of the Carbide to Graphite Transformation on Ni

Abstract

Recent effective medium theory calculations indicate that a nucleation step must be involved in the carbide to graphite transformation on Ni, and that vertical C2 may be a precursor to this nucleation step. A similar nucleation site could also be involved in diamond formation on metals. We interpret previously published C K edge CEELS and NEXAFS data for carbon/Ni between 500-700K. We make comparison with theoretical DOS calculations, and utilize CEELS angle dependencies to assign features and determine bond orientations on the surface. The results confirm that horizontal Cn, most likely C2, exists on the surface up 600K, but that at 620K, some of the species flip up.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1991
Accession Number
ADA231675

Entities

People

  • David E. Ramaker

Organizations

  • George Washington University

Tags

Communities of Interest

  • C4I
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Chemistry
  • Electron Beams
  • Electron Density
  • Electron Energy
  • Electrons
  • Energy
  • Energy Bands
  • Fermi Levels
  • Graphitic Materials
  • High Temperature
  • Intensity
  • Military Research
  • Momentum Transfer
  • Nucleation
  • Orientation (Direction)
  • Precursors
  • Procurement

Fields of Study

  • Physics

Readers

  • Computational Modeling and Simulation
  • Materials Science and Engineering.