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以NH3和C3H8作为反应气体,通过还原-氮化γ-Al2O3可合成制得AlN纳米粉。我们已经通过分析确认:通过NH3和C3H8的混合气流,在1100℃～1400℃保温120min的条件下通过气相还原-氮化γ-Al2O3制得的合成产物中确实存在AlN相,而且在1100℃保温120min后合成制得的产物中还包含未反应的γ-Al2O3。Al核磁共振的图谱显示:产物中的Al-N键随反应温度的提高而增强:[AlO4]四面体比[AlO6]八面体的谐振先削弱,这表明γ-Al2O3中的[AlO4]四面体比[AlO6]八面体更易氮化,基于这一点,可在低温条件下从γ-Al2O3中直接制得AlN纳米粒子。通过气相还原-氮化γ-Al2O3制得AlN纳米粒子的原因是:一方面因为反应温度足够低限制了晶粒生长;另一方面也因为γ-Al2O3只含有[AlO6]一种配位体,而γ-Al2O3则包含两种配位多面体结构即[AlO4]和[AlO6]。
Using NH3 and C3H8 as reaction gases, AlN nanopowders can be synthesized by reducing-nitriding γ-Al2O3. We have confirmed by analysis that the AlN phase did indeed exist in the synthesized product obtained by gas phase reduction-nitriding of γ-Al 2 O 3 through a mixed gas flow of NH 3 and C 3 H 8 under the conditions of holding at 1100 ° C to 1400 ° C for 120 minutes and keeping the temperature at 1100 ° C The product synthesized after 120 min also contains unreacted γ-Al 2 O 3. Al NMR spectra of the products showed that the Al-N bond in the product was enhanced with the increase of the reaction temperature. The resonance of the [AlO4] tetrahedron ratio [AlO6] octahedra first weakened, indicating that the [AlO4] tetrahedron Based on this, AlN nanoparticles can be prepared directly from γ-Al2O3 at low temperature compared with [AlO6] octahedrons. The reason why AlN nanoparticles are prepared by gas-phase reduction-nitriding of γ-Al 2 O 3 is that on the one hand the grain growth is limited because the reaction temperature is low enough; on the other hand, since γ-Al 2 O 3 only contains a ligand of [AlO 6] While γ-Al2O3 contains two kinds of coordination polyhedron structures [AlO4] and [AlO6].