Synthesis of aluminum nitride powder from δ-alumina nanopowders under a mixed gas flow of nitrogen and hydrogen

Aluminum nitride (AlN) was synthesized by calcining δ-alumina (δ-Al2O3) nanopowders under a mixed gas flow of nitrogen and hydrogen that was passed over a crucible containing activated charcoal. The conversion 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 1200 °C and the conversion was completed after 5 h at 1600 °C. The hydrogen cyanide (HCN) gas that evolved during the calcination reacted with alumina to form white AlN.