Tathgar, H: Removal of nickel from molten magnesium

The corrosion properties of magnesium alloys strongly depend on the alloy composition and impurities. Heavy elements like nickel, and iron have low solubility in solid magnesium. The dissolved elements in molten magnesium precipitate out on solidification and form intermetallic particles that are the cause of corrosion. Iron content should be kept below the standards specified by ASTM B94/94 using aluminium and manganese. Manganese forms intermetallic particles with iron and aluminium thereby lowering the solubility of iron, and these particles are cathodic compared to magnesium matrix. No method for the removal of nickel has been known previously. Dissolution was the only method to lower the nickel content. Published solubility data for nickel in pure magnesium is inconsistent and not available for magnesium alloys. Therefore various systems are studied to determine the behaviour of nickel in Mg-Al alloys. Methods for removal of nickel from Mg-Al alloys are also discussed.