CHARACTERIZATION OF DEGRADED SURFACES OF AL AND AIN ULTRAFINE POWDERS

Aluminum (Al) and aluminum nitride (AlN) ultrafine powders (UFPs) were synthesized by an active plasma-metal reaction method. Temperature-pr ogrammed gas Desorption (TPD) measurements were conducted for the Al a nd/or AlN UFPs after exposure to air. H2O gas for AlN UFPs and H2O and H-2 gases for (Al+AlN) UFPs were mainly defected. The surface chemist ry of the powders after exposure to air is estimated in comparison of the desorption characteristics with infrared spectrometry spectra. The evolved H-2 around 420 degrees C from the (Al+AlN) UFPs is due to the reaction of H2O with inner Al. The evolved H2O is considered to be fo rmed by the reaction of adsorbed H2O on surface oxide of the powders a nd decomposition of hydroxide-like compounds.