泡沫前驱体碳热还原氮化法合成氮化铝粉体(英)

Synthesis of Al N Powder by Carbothermal Reduction-nitridation of Alumina/Carbon Black Foam

本研究采用碳热还原氮化法(CRN)合成Al N粉体。以γ-Al_2O_3和炭黑为原料,采用直接发泡工艺与注凝成型相结合的方法制备出Al_2O_3/C泡沫,作为合成Al N粉体的前驱体。泡沫孔隙尺寸从几十微米到几百微米,总孔隙率56%~90%。具有通孔结构的泡沫前驱体实现了原料内部各处的均匀的固–气反应,泡沫总孔隙率≥80%可显著提高CRN反应的速率。XRD分析结果显示:CRN过程中存在γ-Al_2O_3到α-Al_2O_3的相转变,反应起始温度在1300℃以上,并在1550℃反应完全。在1650℃合成得到的Al N颗粒平均粒径不超过1μm,氮含量为32.9wt%。

Alumina/carbon black foam was prepared by mechanical foaming and aqueous gelcasting and used as precursor for the production of Al N powder. The foam with large open pores ensures homogeneous solid-gas reaction during carbothermal reduction-nitridation（CRN） process. Further, the solid-gas contact is enlarged by oppositely feeding the foam and nitrogen in a vertical furnace. Solid-gas reaction efficiency of the CRN process was greatly enhanced when total porosity of the foam was ≥80%. XRD results revealed that γ-Al2 O3 transformed to α-Al2 O3 and then was carbothermal reduction-nitridationed to be Al N phase. Al N powder with an average particle size of less than 1 μm was synthesized at 1650℃ and contained 32.9 wt% nitrogen.