Coating of Fe, Ni onα-alumina microspheres by heterogeneous precipitation

来源期刊：中南大学学报(英文版)2006年第1期

论文作者：沈湘黔 李东红 景茂祥 李旺兴

文章页码：22 - 26

Key words：heterogeneous precipitation; metal-coated alumina microsphere; Ni;α-Fe

Abstract: 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 andα-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 2 h, 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 15 g/L, rate of adding reactants of 5 mL/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.

基金信息：the National Natural Science Foundation of China