Reactive plasma atomization of aluminum nitride powder

Experiments were performed to synthesize AIN powders by reacting Al with N using a conventional DC are plasma as a hear source. Attempts to form AIN powders by feeding Al powder into an argon/nitrogen plasma open to the atmosphere produced mainly aluminum oxide. Subsequent experiments were run inside a chamber which was backfilled with nitrogen. The nitrogen environment suppressed the formation of aluminum oxide, but little AIN was formed by using Al powder as the feedstock material. A furnace and crucible assembly was designed to feed molten A directly into a DeLaval nozzle attached to the face of the DC are plasma gun. The submicron powders formed using this arrangement show a significant increase in the level of AIN formation. The presence of AIN was verified by chemical analysis and X-ray diffraction. Results were dependent upon chamber pressure, plasma velocity and molten liquid feed rate. The experimental parameters, equipment design and results will be reported in detail. The effects of atomization, vaporization and condensation on the reaction product will be discussed.