Surface oxidation of Al-Cu-Fe alloys: a comparison of quasicrystalline andcrystalline phases

We have used X-ray photoelectron spectroscopy and Auger electron spectrosco py to examine the characteristics of oxide surfaces on a family of Al-Cu-Fe alloys. The alloys studied are compositionally similar but structurally di fferent: two are crystalline and one is quasicrystalline. The samples all a re formed by consolidation of powders, resulting in multiple grains with ra ndom surface orientations. They are oxidized to saturation in a variety of environments at room temperature. Under the conditions of our experiments, there is no detectable difference in the oxidation characteristics of the t hree phases. That is, there is no difference in the elemental constituents which oxidize, or in the relative extent of oxygen-induced Al segregation, or in the depth of the oxide formed. Hence, the oxidation chemistry of thes e alloys is determined by their Al-rich chemical composition, and not by th eir atomic or electronic bulk structure, under these conditions.