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

Alumina/carbon black foam was prepared by mechanical foaming and aqueous gelcasting and used as precursor for the production of AlN 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 -Al 2 O 3 transformed to -Al 2 O 3 and then was carbothermal reduction-nitridationed to be AlN phase. AlN powder with an average particle size of less than 1 m was synthesized at 1650 and contained 32.9wt% nitrogen.