Synthesis of AlN Ultrafine Powders by Carbothermal Reduction and Nitridation Method

In order to reduce the reaction temperature and powder size of AlN synthesized by carbothermal reduction and nitridation method and shorten the reaction time,AlN ultrafine powders were prepared at different temperatures with boehmite (γ-AlOOH) as aluminum resource and sucrose (C12H22O11) as carbon resource.Phase compositions and appearance of the prepared powders were analyzed by XRD and SEM.The results show that AlN powders with average grain size of 350 nm could be obtained with holding time of 1 h at 1 480 ℃ in flowing N2 atmosphere,which dramatically reduced the reaction temperature and shortened the reaction time.At high temperature,γ-AlOOH decomposed into Al2O3,and then partial Al2O3 was reduced by carbon to aluminum vapor,Al2O and AlO which could react with nitrogen to form AlN and AlON intermediate phase.Then AlON gradually transformed to AlN by further reaction with carbon or CO.