Magnesium alloys are well known for their high affinity for oxygen and highly reactive
characteristics. This has created difficulties in their processing. During melting, a protective
film generated by chloride or fluoride based flux or an inert atmosphere created by
a specific gas combination, is required to isolate the melt from the atmosphere in order
to suppress any reaction.
At the casting stage, reaction with some mould materials is likely to happen. This has
caused a serious problem in the casting of magnesium, particularly with the investment
casting process. The mould-metal interface reaction must be eliminated or minimized if
the production of castings with close tolerances and good surface finish is to be achieved. [Continues.
