High-temperature oxidation of Al-Mg alloys

The effect of the atmosphere on the oxidation rates of aluminum-can alloys was studied using thermogravimetric methods. The atmospheres included: air, Ar + 1%O-2, Ar + 5%O-2, and CO2. Temperatures ranged from 450 to 800 degre es C. The oxidation rate was influenced by the surface condition and by the time elapsed after specimen preparation. Increasing temperature increased the oxidation rate of both AA 3004 and 5182. Parabolic kinetics were observ ed for AA 3004 and linear kinetics were observed for AA 5182 at 450 and 500 degrees C. From 550 to 800 degrees C, parabolic behavior was observed for AA5182. The reduction of free oxygen in the atmosphere reduced the rate of oxidation. The reactivity of the atmospheres decreased in the following seq uence: air, Ar+5%O-2, Ar+1%O-2, and CO2.