Oxidation behavior of molten magnesium in atmospheres containing SO2

The microchemistry and morphology of the oxide layer formed on molten magnesium in atmospheres containing SO₂ were examined. Based on the results and the thermodynamic and kinetic calculations of oxide-growth process, a schematic oxidation mechanism is presented. The results showed that the oxide scales with network structure were generally composed of MgO, MgS, and MgSO₄ with different layers, depending on the SO₂ content, the time and the temperature. The formation of MgSO₄ was important for the formation of the protective oxide scales. The growth of the oxide scales followed the parabolic law at 973 K and was controlled by diffusion.