Highly crystalline AlN particles synthesized by SHS method

Aluminium nitride (AlN) powders were prepared by self-propagating high-temperature synthesis (SHS). Aluminium and AlN powder mixtures with weight ratios of about 60:40, in the absence and in the presence of 3-wt.% NH4F and 3-wt.% NH4F + 3-wt.% carbon powders as additives were ignited in a nitrogen atmosphere of 8 MPa. Highly crystalline AlN particles with regular hexagonal morphology were obtained in the presence of 3-wt.% NH4F + 3-wt.% carbon. The microstructure development during the reaction and the influence of these additives were determined by SEM/EDS and XRD analysis of the resulting products. A mechanism for the formation of AlN with a regular hexagonal morphology has been suggested.