화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.89, No.1, 171-175, 2006
Synthesis of AlN nanopowder from gamma-Al2O3 by reduction-nitridation in a mixture of NH3-C3H8
Aluminum nitride (AlN) powders were synthesized by gas reduction-nitridation of gamma-Al2O3 using NH3 and C3H8 as the reactant gases. AlN was identified in the products synthesized at 1100 degrees-1400 degrees C for 120 min in the NH3-C3H8 gas flow confirming that AlN can be formed by the gas reduction-nitridation of gamma-Al2O3. The products synthesized at 1100 degrees C for 120 min contained unreacted gamma-Al2O3. The Al-27 MAS NMR spectra show that Al-N bonding in the product increases with increasing reaction temperature, the tetrahedral AlO4 resonance decreasing prior to the disappearance of the octahedral AlO6 resonance. This suggests that the tetrahedral AlO4 sites of the gamma-Al2O3 are preferentially nitrided than the AlO6 sites. AlN nanoparticles were directly formed from gamma-AlO3 at low temperature because of this preferred nitridation of AlO4 sites in the reactant. AlN nanoparticles are formed by gas reduction-nitridation of gamma-Al2O3 not only because the reaction temperature is sufficiently low to restrict grain growth, but also because gamma-Al2O3 contains both AlO4 and AlO6 sites, by contrast with alpha-Al2O3 which contains only AlO6.