Magnesium has the lowest density of all structural alloys, making it 33% lighter than aluminum and 75% lighter than steel. Despite the lower density, magnesium alloys are both stiffer and stronger weight-for-weight than aluminum.

Magnesium’s high reactivity had made it susceptible to corrosion. However, recently discovered alloys and higher-purity variants of traditional alloys have a much greater resistant to corrosion, and new coating techniques such as plasma electrolytic oxidation (PEO) make a thoroughly resistant neutral oxide from the metal’s substrate.