A STUDY ON THE TECHNIQUE OF PREPARING ULTRAFINE AlN POWDER BY ARC PLASMA

This paper persentes the method of preparation of ultrafine AIN powder by D.G arc plasma.Two kinds of AlN Powders were produced respectively in two diffcrent mixed gases, N₂-Ar and N₂-NH₃, by the nitridation reaction of the aluminium metal vapor evaporated by means of D.C arc plasma. The experimental results have shown that the Powder prepared in N₂-Ar gas always a mixture of Al and AlN powders, while in the N₂-NH₃ gas a pure ultrafine AlN Powder can be produced. By means of X-ray diffraction analysis, it was shown that the ultafine AlN powder produced in the N₂-NH₃ gas with a appropriate mix ratio of N₂ and NH₃ has no Al powder, i.e., the nitridation ratio of alu minium is 100%.
The most probable diameter and the mean diameter measured by electronmicroscope are 5.29nm and 21.0nm respectively. In the last paragraph of this paper the actions of arc plasma, the mechanism of generating ultrafine AlN particles and the factors exerting an influence on the AlN content in the powder have been discussed.