碳热还原法制备AlN超微粉工艺和材料研究

Synthesis of AlN Ultrafine Powder by Carbothermal Reduction Nitridation Method and Material Research

以勃母石(γ-AlOOH)和蔗糖为原料,采用碳热还原法在1480℃、N2气氛中保温60min,制备出平均粒径为350nm的AlN粉。勃母石、蔗糖在高温作用下分解成粒度小、活性大的γ-Al2O3和C,有效降低了反应激活能,提高了反应效率,降低了反应温度,缩短了反应时间。其反应合成机理为:在高温下,部分Al2O3被C还原成气态Al和Al的低价氧化物(Al2O,AlO),它们与N2直接反应生成AlN和中间相AlON。随着反应的进行,中间相AlON逐步生成AlN。

AIN ultrafine powder （350nm in particle diameter） is synthesized from boehmite （γ-AlOOH） and su- crose （C12 H22O11 ） using a carbonthermal reduction-nitridation process at 1480℃for 60 minutes in flowing N2. Bo-eh- mite and sucrose transform to ultrafine and highly reactive γ-Al2O3 and carbon powders at high temperature, which ef- fectively reduces the activation-energy of the earbothermal reduction-nitridation reaction and accelerates the reaction rate, resulting in a lowered reaction temperature. The reaction mechanism is that at the reaction temperature, a part of the aluminum oxide is reduced to aluminum vapor, Al2O and/or AlO by C, and they react with nitrogen to form AlN and an intermediate AlON phase. AlON gradually transforms to AlN by the further reaction with C or CO.