ELECTRON-ENERGY-LOSS NEAR-EDGE STRUCTURE OF METAL-ALUMINA INTERFACES

The physical properties of metal-ceramic composites are strongly affec ted by the local chemistry and atomic bonding across the interface. In formation 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 inv estigation of two different interfaces, namely Al/Al2O3 and Cu/Al2O3. The Al-L(2,3) edge at the Al/Al2O3 interface shows a characteristic en ergy-loss near-edge structure which was compared to multiple scatterin g calculations for Al(O3Al) tetrahedra with various Al-Al bond lengths . Good agreement with the experimental data was found for a cluster wi th an A-Al bond length larger than the Al-O distance which is nearly t hat of amorphous Al2O3 NO interface-specific component could be detect ed at the Al-L(2,3),3 edge of the Cu/Al2O3 interface. However, the ene rgy-loss near-edge structure of the Cu-L(2,3) edge indicates that Cu e xists at the interface in a Cu1+ state and that the chemical bond is e stablished at the interface between Cu and O atoms.