Abstract
An experimental study on the nonsteady ignition process of magnesium and 50-50 magnesium-aluminum alloy was made by using the stagnation region of an impinging hot air stream. The study has revealed that the ignition of magnesium was caused to occur through a four-stage surface oxidation process and finally through a homogeneous exothermic reaction in the gaseous phase. The ignition mechanism of the magnesium-aluminum alloy was essentially identical with that of magnesium, although the observed ignition behavior was more complicated. The difference could be explained in terms of the aluminum ingredient contained in the oxide film formed on the sample surface.