Transition-Al2O 3 nanopowder was first prepared by the precipitation-coated method combined with the freeze drying technique by using AlCl3·6H2O, ammonia, ammonium chloride （NH4Cl） as raw materials, and then ch...Transition-Al2O 3 nanopowder was first prepared by the precipitation-coated method combined with the freeze drying technique by using AlCl3·6H2O, ammonia, ammonium chloride （NH4Cl） as raw materials, and then characterized with X-ray diffraction （XRD）, thermogravimetric analysis （TGA）, differential scanning calorimetry （DSC）, BET surface area and particle size analyzer.Coating precipitation surface with NH4Cl, adding surface activator, washing with ethanol and freeze drying were used to decrease particle agglomeration.γ-Al2O3 nanopowder with an average diameter of 6.73 nm and γ-δ-Al2O3 nanopowder with an average diameter of 11.92 nm were obtained by calcination of the precursors at 600℃ and 950℃, respectively.Phase transformation of Al2O 3 ,the principle of precipitation surface coated by NH4Cl and the mechanism of anti-agglomeration via surface coating were also investigated.展开更多
文摘Transition-Al2O 3 nanopowder was first prepared by the precipitation-coated method combined with the freeze drying technique by using AlCl3·6H2O, ammonia, ammonium chloride （NH4Cl） as raw materials, and then characterized with X-ray diffraction （XRD）, thermogravimetric analysis （TGA）, differential scanning calorimetry （DSC）, BET surface area and particle size analyzer.Coating precipitation surface with NH4Cl, adding surface activator, washing with ethanol and freeze drying were used to decrease particle agglomeration.γ-Al2O3 nanopowder with an average diameter of 6.73 nm and γ-δ-Al2O3 nanopowder with an average diameter of 11.92 nm were obtained by calcination of the precursors at 600℃ and 950℃, respectively.Phase transformation of Al2O 3 ,the principle of precipitation surface coated by NH4Cl and the mechanism of anti-agglomeration via surface coating were also investigated.
