Morphology-controlled Synthesis of Hexagonal AlN Whiskers by Direct Nitridation of Aluminum and Alumina Mixture

Abstract

Hexagonal 1D AlN whiskers were synthesized by direct nitridation of aluminum and alumina. The effect of the atmosphere was investigated based on thermodynamic calculation. A green body compacting alumina with different particle size in between 44–420 μm in graphite crucible was found to be favorable for the large-scale synthesis of AlN at 1650 °C for 3 h in flowing nitrogen atmosphere. XRD result indicated that hexagonal AlN phase with high purity has been successfully synthesized. SEM and TEM analysis indicated that the whiskers possessed uniform morphology with 100–200 nm in diameter and length up to microns. The formation mechanism was further proposed based on the experimental results.