Aluminium nitride (AlN) nanopowder was successfully synthesized from transition alumina nanopowder via a new single-step nitridation process. A gas mixture of NH_3-C_3H_8 was employed as a reduction-nitridation agent, which enables direct nitridation of transition alumina at processing temperatures of 1200-1400 deg C. AlN powder prepared under typical reaction conditions was found to be phase-pure and nanocrystalline, with a specific surface area of 36.4 m~2 g~(-1) and a mean particle size around 50 nm. The AlN nanopowders produced could be densified to a pore-free state in conventional processing, without resort to the use of sintering aids. SEM observation revealed markedly small grain sizes in the sintered specimens compared with the commonly processed AlN.
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