Free Access
Microsc. Microanal. Microstruct.
Volume 6, Number 1, February 1995
Page(s) 19 - 31
Microsc. Microanal. Microstruct. 6, 19-31 (1995)
DOI: 10.1051/mmm:1995104

Electron Energy-Loss Near-Edge Structure of Metal-Alumina Interfaces

Christina Scheu1, Gerhard Dehm1, Harald Müllejans1, Rik Brydson2 et Manfred Rühle1

1  Max-Planck-Institut für Metallforschung, Institut für Werkstoffwissenschaft Seestraße 92, 70174 Stuttgart, Germany
2  Department of Materials Science and Engineering, University of Surrey, Guildford GU2 5XH, U.K.

The physical properties of metal-ceramic composites are strongly affected by the local chemistry and atomic bonding across the interface. Information on both are contained in the energy-loss near-edge structure. The spectral component specific for the interface can be obtained by the spatial- difference technique. This method was applied for the investigation of two different interfaces, namely Al/Al2O3 and Cu/Al2O3. The Al-L2,3 edge at the Al/Al2O3 interface shows a characteristic energy-loss near-edge structure which was compared to multiple scattering calculations for Al(O3Al) tetrahedra with various Al-Al bond lengths. Good agreement with the experimental data was found for a cluster with an Al-Al bond length larger than the Al-O distance which is nearly that of amorphous Al2O3. No interface-specific component could be detected at the Al-L2,3 edge of the Cu/Al2O3 interface. However, the energy-loss near-edge structure of the Cu-L2,3 edge indicates that Cu exists at the interface in a Cu1+ state and that the chemical bond is established at the interface between Cu and O atoms.

7920K - Other electron surface impact phenomena.
8280D - Electromagnetic radiation spectrometry chemical analysis.
6848 - Solid solid interfaces.

Key words
alumina -- aluminium -- copper -- electron energy loss spectra -- interface structure -- spectrochemical analysis -- metal alumina interfaces -- metal ceramic composites -- atomic bonding -- spatial difference technique -- multiple scattering calculations -- Al Al bond lengths -- ELNES -- Al Al sub 2 O sub 3 -- Cu Al sub 2 O sub 3

© EDP Sciences 1995