OXIDATION OF AlMg IN DRY AND HUMID ATMOSPHERES

摘要

Thermal oxidation of Al5%Mg was carried out in dry and humidatmospheres with a thermogravimetric analyzer (TGA), and thecomposition of off-gases was measured with a mass spectrometer.It was found that when water vapor participates in oxidation,hydrogen gas is produced. A humid atmosphere (7 mol% H_2O)does not affect total oxidation mass, but seems to catalyzeoxidation in both air and air containing 5 mol% CO_2. In an airatmosphere containing 5 mol% CO_2, total oxidation isapproximately 50-75 % less than in air alone. Some samples inhumid air (7 mol% H_2O) containing 5 % CO_2 did not oxidizesignificantly, which may be due to a strong oxide layer whichforms around the liquid aluminum sample. A carbon powdercoating was shown to protect the aluminum from oxidation for anextended period of time compared to an unprotected sample andhumidity extended this protection. This work has potentialapplications in industrial thermal decoating units.