Use of melamine in the nitridation of aluminum oxide to aluminum nitride

By using melamine as a nitridizing reagent, aluminum nitride (AlN) powders were prepared from delta- and alpha-alumina (Al2O3) powders which had not been mixed with carbon. The hydrogen cyanide (HCN) formed by thermal decomposition of melamine was involved in the nitridation of Al2O3 to AlN. The nitridation process of alumina to AlN was monitored by powder X-ray diffraction patterns and Al-27 magic-angle spinning nuclear magnetic resonance spectroscopy. delta-Al2O3 began to be converted to AlN at 1050 degrees C without delta-alpha alumina transformation. The nitridation rate of delta-Al2O3 was much higher than that of alpha-Al2O3. (C)2011 The Ceramic Society of Japan. All rights reserved.