Nanosized Al2O3 particles homogeneously dispersed in a matrix of amorphous carbon (a-C) were prepared by decomposition of an aluminum oleic emulsion at 600 degrees C in Ar. Nanosized aluminum nitride (AlN) grains were prepared by carbothermal reduction and nitridation (CRN) of this Al2O3-a-C mixture in NH3 using graphite, BN, and alumina crucibles or boats. The phases formed by CRN were identified by X-ray diffraction analysis. The morphology and grain size of the AlN were determined by transmission electron microscopy. The formation of single-phase AlN was achieved at temperatures as low as 1150 degrees-1200 degrees C in NH3 using a cylindrical graphite crucible with holes in its two flat faces. Mass spectroscopy (MS) showed that a significant amount of HCN and a minor amount of C2H2 are formed at 500 degrees C by reaction of NH3 with carbon at the decomposition temperature of NH3. A most probable formation mechanism of the AlN from nanosized Al2O3 and a-C in NH3 is discussed on the basis of MS results and thermodynamic considerations.