Papers by Keyword: Gas Reduction Nitridation

Abstract: Aluminum nitride (AlN) powder was synthesized by gas reduction–nitridation of γ-Al2O3, using NH3 as the reactant gas. The results showed that AlN can be fabricated by this process at 1100°C for over 480 min in the flowing NH3 atmosphere. However, no AlN was found in the products synthesized at 1300°C and 1400°C, which was different from the former reports. A series of experiments with different parameters were carried out, and the effects of reacting temperature and time on the synthesis of AlN were investigated. The reaction mechanism was also studied.

Abstract: AlN powders were synthesized by gas-reduction- nitridation of γ-Al2O3 powders using NH3 and C3H8 as reactant gases. AlN was identified from the products that synthesized at 1100-1400 oC for 120 min in the NH3-C3H8 gas flow, and it was confirmed that AlN can be easily fabricated by the gas-reduction-nitridation of γ-Al2O3. The products synthesized at 1100oC for 120min contained unreacted γ-Al2O3. By the 27A1 MAS NMR spectra, Al-N bonding in the product increased with an increase in the nitridation ratio of the tetrahedral AlO4 shoulder which decreased prior to that of the octahedral AlO6 shoulder. It seems that γ-Al2O3 was preferentially nitrided from AlO4 rather than AlO6. AlN nano particles were easily converted directly from γ -Al2O3 at a low temperature because the AlO4 within γ-Al2O3was preferentially nitrided.