Abstract
Nanosized aluminum nitride (AlN) powders were prepared by calcining δ-alumina (δ-Al2O3) nanopowders under a flow of acetonitrile (CH3CN) diluted in argon. The nitridation process of δ-Al2O3 to AlN was monitored by powder X-ray diffraction patterns and 27Al magic-angle spinning nuclear magnetic resonance spectroscopy. δ-Al2O3 began to be converted to AlN at 1050°C without δ-α alumina transformation and the conversion was completed at 1300°C. The cyanide radical, which was produced by thermal decomposition of CH3CN, reacted with Al2O3 to form AlN. The cyanonitridation method can considerably mitigate the two main drawbacks of the carbothermal reduction and nitridation method: high reaction temperature and intimate mixing of Al2O3 with carbon. Cathodoluminescence spectra of the nanosized AlN powders obtained in this study showed an intense ultraviolet emission band at 376 nm.
