Shape of AlN Powders Prepared by Vapor Phase Reaction of AlCl<sub>3</sub>⋅NH<sub>3</sub>-NH<sub>3</sub>-N<sub>2</sub> System

AlN powders were prepared by vapor phase reaction of AlCl3⋅NH3-NH3-N2 system. AlCl3⋅NH3 was prepared by the evaporation and decomposition of AlCl3⋅nNH3 (n=1.7-1.8) at 430°C. The shape of AlN particles varied with the molar ratio [NH3]/[AlCl3⋅NH3] (X) or the synthesis temperature (TR). At TR=1400°C, AlN particles had columnar crystals at X≤7, but had smooth surface at X≥9. However, at TR=1000°C, AlN particles had smooth surface even at X=4.2.