Corrosion behaviour of aluminium in molten sodium

Abstract Sodium attack of both aluminium (99.999%, 99.8% and 99.5% purity) and Al-12wt.%Si alloy is investigated. Aluminium 99.999% purity is immune, but aluminium of 99.8% or 99.5% purity and the Al-Si alloy are attacked by molten sodium at 350–500 °C. The corrosion product formed on the surface of the materials is identified as the AlNaSi compound. This suggests that sodium attack of aluminium and Al-12wt.%Si alloy is the result of a reaction between sodium and the silicon contained in the aluminium.