Icosahedral Al62Cu25.5Fe12.5 phase in the presence of carbon

Previous studies have suggested that contamination by carbon of the i-Al62Cu25.5Fe12.5 quasicrystalline phase can cause destabilization of the aperiodic structure. Hence, the possibility of carbon diffusion into AlCuFe quasicrystalline thin films and the possible subsequent degradation of the quasicrystalline structure were investigated at room temperature through to 600degreesC. The study shows that a carbon layer deposited on the AlCuFe quasicrystalline thin film did not diffuse into the AlCuFe over the temperature range tested whatever the oxide thickness between carbon and alloy. Moreover, the carbon did not react with any of the alloy elements as has been shown with aluminium, in the presence of oxygen. Post-deposition annealing at 600degreesC of the amorphous alloy, fabricated by simultaneous electron beam evaporation on an amorphous carbon substrate used for transmission electron microscopy (TEM), also leads to a pure quasicrystalline phase thin film without any carbon diffusion from the substrate. (C) 2004 Elsevier B.V. All rights reserved.