Abstract The a-A1₂O₃ nanopowder was prepared by sol-gel method with industrial pure alumina sol as starting material.The effects of peptization condition,addition of seed crystal,addition and kinds of additives,calcination temperature and holding time on the crystal grain size of nano- A1₂O₃ were investigated.The results show that the smaller the particle size after peptization is,the smaller the particle size of product is,and the lower the calcination temperature is.The addition of seed crystal and additive can accelerate the transition alumina changing to a-A1₂O₃,and reduce the phase transformation temperature.The calcination temperature greatly influence the formation of a-A1₂O₃,whereas the holding time has little effect on the phase of product.The spheric granules a-A1₂O₃ nanopowders with 50 nm particle size and with even size distribution are obtained under the optimum condition of 1 wtï¼…triethanolamine,5 wtï¼…seed crystal,5 wtï¼…NH₄ NO₃addition,1000 ^oC for calcination temperature and 2 h holding time.

Keywords a-A1₂O₃ nanopowder;sol-gel method;processing parameter

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