Effect of urea on synthesis of aluminum nitride powders from aluminum nitrate and glucose

AlN powders were synthesized by carbothermal reduction method from aluminum nitrate and glucose.The effect of urea on the preparation and nitridation of the precursors was studied. It is found that urea can affectthe morphology and composition of the precursor as well as the nitridation process. During the nitridation process ofthe precursor prepared without urea, α-A12 O3 and A1ON are detected and a high temperature(1600 ℃ ) is needed fora complete conversion. While for the precursor prepared with urea, a complete conversion is got at a relatively lowtemperature(1 400 ℃ ) and AlN is synthesized directly from γ-Al2 O3, with no sign of the formation of α-Al2 O3 andAlON. AlN powders synthesized from the precursor prepared without urea agglomerate badly, while the powderssynthesized from the precursor prepared with urea are soft aggregates of fine particle, which can be easily dispersed.