The oxidation at 500 °C of AlCuFe quasicrystalline powders: A X-ray diffraction study

The oxidation behavior at 500 °C of AlCuFe icosahedral quasicrystalline powders was investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Powders have been characterized at room temperature before and after oxidation. Oxidation leads to a long-range diffusion of aluminum atoms, which form an amorphous oxide layer on top of the grains. When the loss of aluminum inside the grains is too high, the icosahedral phase transforms in cubic β-phase (CsCl type). This transformation no longer occurs when the grain size is higher than a critical value.