Synthesis of aluminum nitride in a coke–calcium reduction bed using nitrogen in air

An experimental study on the heating of a mixture of aluminum and lithium hydroxide (LiOH) powders in a reductive bed under air atmosphere is reported. The formation of aluminum nitride (AlN) during this process was the focus of this study. The formation of AlN was achieved using LiOH as an additive and heating the sample in a resistance furnace in a specially designed double crucible within a bed of a mixture of coke and filamentous calcium. The temperature range of the reaction was between 700℃ and 1100℃. The optimum temperature of 1100℃ and the optimum LiOH amount (5wt%) required to achieve maximum yield were determined by powder X-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) micrographs clearly indicated the transformation of grain structures from rods (700℃) to cauliflower shapes (1100℃).