Like aluminium, magnesium reacts spontaneously with oxygen to its oxide. This reaction is highly exothermic. Unlike aluminium oxide, magnesium oxide is porous and does not give protection for further oxidation. Therefore, liquid magnesium has to be protected from ignition in order to be safely handled.

One way of protecting a magnesium melt is to modify the oxide layer in such a way that it becomes dense. Some gas mixtures are known to protect molten magnesium by creating such a dense oxide film on the surface. However, the most common gas mixtures for this purpose have SF6 as active component. SF6 has been shown to affect the environment in a negative way by contributing to an increased greenhouse effect. SF6 has a global warming potential of 24000 times relative to CO₂.

The core competences at SINTEF regarding research on magnesium are:

• Casting and foundry technology.
• Melt and gas flow modelling.
• Melt protection.
• Melt treatment.
• Melt cleanliness.
• Alloy development and characterisation.

Figure: Computer model and actual magnesium part. The part is a B-pole for a car.