Fabrication of Fe-, Ni- and FeNi-coated Al2O3 core-shell microspheres by heterogeneous precipitation |
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Authors: | Xiang-qian Shen Mao-xiang Jing Wang-xing Li Dong-hong Li |
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Affiliation: | aSchool of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China bZhengzhou Research Institute of Chalco, Zhengzhou 450041, China |
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Abstract: | The precursors with NiCO3·2Ni(OH)2·2H2O-, Fe2O3·nH2O-, or both of NiCO3·2Ni(OH)2·2H2O- and Fe2O3·nH2O-coated alumina microspheres were prepared, respectively, by the aqueous heterogeneous precipitation using metal salts, ammonium hydro-carbonate and -Al2O3 micropowders as the starting materials. Subsequently, magnetic metallic Ni-, -Fe- and γ-FeNi-coated alumina core-shell structural microspheres were successfully obtained by thermal reduction of the as-prepared precursors at 700 °C for 2 h, respectively. Optimized precipitation processing parameters of the concentration of alumina micropowders (15 g/L), the rate of adding reactants (5 mL/min) and pH value were determined by a trial and error method. Powders of the precursors and the resultant metal (Ni, -Fe, γ-FeNi alloy)-coated alumina micropowders were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The experimental results show that it is possible to adjust metal coating thicknesses and fabricate multilayer structured metal/ceramics core-shell microspherical powder materials and these materials may be applied for high performance of functional materials and devices. |
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Keywords: | Heterogeneous precipitation Core-shell structure Alumina microsphere Metal-coated |
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