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The fractured, polished and Ar + ‐sputtered surfaces of natural enargite: an XPS study
Author(s) -
Velásquez P.,
RamosBarrado J. R.,
Leinen D.
Publication year - 2002
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.1300
Subject(s) - x ray photoelectron spectroscopy , chalcocite , stoichiometry , analytical chemistry (journal) , surface layer , chemistry , ion , annealing (glass) , mineralogy , layer (electronics) , metallurgy , copper , materials science , chalcopyrite , physics , nuclear magnetic resonance , organic chemistry , chromatography
The natural mineral enargite (Cu 3 AsS 4 ) has been studied by XPS combined with 4 keV Ar + depth profiling. The fracture surface, the mechanically polished surface and the 4 keV Ar + ‐bombarded enargite surface has been studied by XPS. The fracture surface reveals a stoichiometry in accordance with Cu 3 AsS 4 , whereas the polished and the ion‐bombarded surface show strong deviations. In the polished surface a loss of As and Cu leads to polysulphide formation at the sample surface. Enargite subjected to 4 keV Ar + bombardment reveals a preferential loss of As and, to a lesser extent, sulphur atoms from the sample surface, yielding a steady‐state composition near to chalcocite (Cu 2 S). The compositional change in the ion‐bombardment‐altered layer is discussed in terms of the thermal spike model, taking into account the volatility of the constituent atoms or possible compounds in the altered layer. Copyright © 2002 John Wiley & Sons, Ltd.