Fabrication of magnetic nanosized γ-FeNi-coated ceramic core–shell microspheres by heterogeneous precipitation and thermal reduction--颗粒学报PARTICUOLOGY

Li, D., Zhou, J., Shen, X., & Liu, W. (2010). Fabrication of magnetic nanosized γ-FeNi-coated ceramic core–shell microspheres by heterogeneous precipitation and thermal reduction. Particuology, 8(3), 257-261. https://doi.org/10.1016/j.partic.2009.05.008

Fabrication of magnetic nanosized γ-FeNi-coated ceramic core–shell microspheres by heterogeneous precipitation and thermal reduction

Donghong Li ^{a b}, Jianxin Zhou ^a, Xiangqian Shen ^a *, Wei Liu ^a

a School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China
b Zhengzhou Research Institute of Chalco, Zhengzhou 450041, China

10.1016/j.partic.2009.05.008

Volume 8, Issue 3, June 2010, Pages 257-261

Received 29 December 2008, Revised 5 May 2009, Accepted 16 May 2009, Available online 28 April 2010.

E-mail: shenxq@ujs.edu.cn

Highlights

Abstract

Precursors with NiCO₃·2Ni(OH)₂·2H₂O- and Fe₂O₃·nH₂O-coated alumina, graphite and cenosphere were synthesized by precipitation using ferrous sulfate, nickel sulfate, ammonium bicarbonate, alumina, graphite and cenosphere as the main starting materials. Magnetic γ-FeNi-coated alumina, graphite and cenosphere core–shell structural microspheres were subsequently prepared by thermal reduction of the as-prepared precursors at 600 °C for 2 h. Precipitation parameters, e.g. concentration of ceramic micropowders (10 g/L), sulfate solution (0.2 mol/L), rate of adding reactants (3 mL/min) and pH value were optimized by a trial-and-error method. Powders of the precursors and the resulting coating of γ-FeNi with grain size below 40 nm on alumina, graphite and cenosphere microspheres were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The magnetic properties of the nanosize γ-FeNi-coated alumina, graphite and cenosphere microspheres were measured by vibrating sample magnetometer (VSM). The results show that the core–shell structural γ-FeNi-coated ceramic microspheres exhibited higher coercivity than pure γ-FeNi powders, indicating that these materials can be used for high-performance functional materials and devices.

Graphical abstract

Keywords

Heterogeneous precipitation; Core–shell structure; γ-FeNi-coated; Magnetic property

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