Oxidation behavior of molten magnesium in atmospheres containing SO2 and air in a sealed furnace

► Molten Mg can be fully protected in the atmosphere containing SO2, air and N2. ► Partially protective films have a two layer structure and contain MgO and MgS. ► Fully protective films have a four layer structure and contain MgO, MgS and MgSO4. ► An increase in SO3 pressure in the cover gases increases the protective effect.