The high-temperature oxidation of some oxidation-resistant copper-based alloys.

The oxidation behavior of Cu-2Be, Cu-5Al, Cu-8Al, Cu-3Si, Cu-2Al-2Si, Cu-2.5Al-2.5Si, Cu-4.5Al-2Si, Cu-7.5 Al-2Si, Cu-6.5Al-4Si, and Cu-4.5Al-5Si, in the temperature range 100-800°C, in air, has been investigated by gravimetric measurements and by electron microscopical examination of stripped oxide films. Most of the alloys showed considerable resistance to oxidation. This was given mainly by a thermally grown film of γ-alumina on the Cu-Al and Cu-Al-Si alloys and by a beryllia film on the Cu-Be alloy. Other oxide phases, principally copper oxides, were also found to grow on the alloys and these are described. Silicon additions to Cu-Al alloys are found to improve their oxidation resistance, although no crystalline oxides containing silicon were observed in the oxide films stripped from the Cu-Al-Si alloys. [ABSTRACT FROM AUTHOR]