High-temperature oxidation of Al–Cu–Fe–Be quasicrystalline powders

The oxidation behavior in air of gas atomized Al–Cu–Fe–Be powders was investigated during isothermal exposures at 750, 800, and 830 °C. Oxidation data obtained at 750 °C for Al–Cu–Fe and Al–Cu–Fe–Cr powders are also presented and used as references. Thermogravimetric analyses showed that Be significantly improved the oxidation resistance of the icosahedral phase at 750 °C. At this temperature the i-phase in Al–Cu–Fe–Be powders was found to be stable even after oxidation for 300 h, while oxidation at and beyond 800 °C led to the formation of a cubic β′-phase. Auger analyses suggested that, in addition to its role on the stability of the icosahedral phase, the presence of Be in the oxide layer provided efficient protection against air oxidation at high temperature.