The precursors with NiCO3·2Ni（OH）2·2H2O, Fe2O3·nH2O coated alumina microspheres were prepared by the aqueous heterogeneous precipitation using metal salts, ammonium bicarbonate and α-Al2O3 micropowde...The precursors with NiCO3·2Ni（OH）2·2H2O, Fe2O3·nH2O coated alumina microspheres were prepared by the aqueous heterogeneous precipitation using metal salts, ammonium bicarbonate and α-Al2O3 micropowders as the starting materials. Magnetic metal Ni, α-Fe coated alumina, core-shell structural microspheres were successfully obtained by thermal reduction of the precursors at 700℃ for 2h, respectively. Powders of the precursors and the resultant metal （Ni, α-Fe） coated alumina micropowders were characterized by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The results show that optimized precipitation parameters are concentration of alumina micropowders of 15g/L, rate of adding reactants of 5mL/min and pH value of 7.5. And under the optimized conditions, the spherical precursors without aggregations or agglomerations are obtained, then transferred into Ni, α-Fe coated alumina microspheres by thermal reduction. It is possible to adjust metal coating thicknesses and fabricate a multilayer structured metal/ceramics, core-shell microspherical powder materials.展开更多
文摘The precursors with NiCO3·2Ni（OH）2·2H2O, Fe2O3·nH2O coated alumina microspheres were prepared by the aqueous heterogeneous precipitation using metal salts, ammonium bicarbonate and α-Al2O3 micropowders as the starting materials. Magnetic metal Ni, α-Fe coated alumina, core-shell structural microspheres were successfully obtained by thermal reduction of the precursors at 700℃ for 2h, respectively. Powders of the precursors and the resultant metal （Ni, α-Fe） coated alumina micropowders were characterized by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The results show that optimized precipitation parameters are concentration of alumina micropowders of 15g/L, rate of adding reactants of 5mL/min and pH value of 7.5. And under the optimized conditions, the spherical precursors without aggregations or agglomerations are obtained, then transferred into Ni, α-Fe coated alumina microspheres by thermal reduction. It is possible to adjust metal coating thicknesses and fabricate a multilayer structured metal/ceramics, core-shell microspherical powder materials.
