| dc.description.abstract | The purpose of this study is analyzing the thermal-formed oxide on aluminum and magnesium alloys. Two materials, Al-2wt%Mg、Al-4wt%Mg were used in this study. The cube samples were prepared in 10 mm × 10 mm × 6 mm. They were then polished by ＃400, ＃800, ＃1200, ＃1500 and ＃2000 abrasive paper. These cube samples were moved to the muffle furnace in the air and nitrogen separately and then heated to 500℃ and hold on for 1 hr,6hrs,25hrs.
The experimental result find that the magnesium oxide and Gibbs-free energy are lower than the alumina, and the oxide film gradually is rich in oxygen and magnesium, the surface oxide layer which almost entirely magnesium oxide, so Al-Mg alloy oxide film is mainly the magnesium oxide for heating of air. The Al-2wt%Mg thermal oxide film appearance with alumina, MgO, MgAl2O4 spinel, and MgO appeared first on the surface of the sample and followed by formation MgAl2O4 spinel. The Al-2wt%Mg thermal oxide film doesn’t observe MgAl2O4 spinel, to transform MgAl2O4 spinel is depend on the content of Mg of Al-Mg alloy.
When Al-Mg alloy heat in the nitrogen, the surface is formed aluminum nitride and magnesium nitride, Mg react with nitrogen to form Mg3N2, then react and form AlN with aluminum. Formulation amount of the AlN is related to content of Mg of Al-Mg alloy. During long heat of time with nitrogen, the deleterious effect of oxygen impurities is due to its inhibition to the chemisorbtion of N2 molecules, then Mg3N2 and AlN transform to MgO and Al2O3 separately. | en_US |