Combustion of Al–Al2O3 mixtures in air

An experimental study on the aluminum oxynitride and aluminum nitride formation by combustion of mixtures of micron-sized aluminum powder (average particle diameter as ∼9.0 μm) and alumina nanopowder (as ∼0.05 μm) of the fixed mass (∼10 g) and different mass ratios (Al/γ-Al2O3 = 0.1–19.0) in air is reported. The formation of aluminum oxynitride (Al3O3N) and aluminum nitride during the combustion of powdery aluminum-based mixtures in air is discussed in this study. The combustion synthesis of Al3O3N and AlN was carried out in self-sustaining way. XPS-FESEM, XRD and chemical analysis were executed on final products of synthesis. The combustion process was also recorded by a video-camera. It was found that powdery mixtures, ignited by local heating, burned in one- or two-stage self-propagating regime. The combustion regime is different for different initial mass ratios Al/γ-Al2O3 and mainly depends on the content of fuel (aluminum powder) in mixture.