Preparation of ferromagnetic metal fine fibers by organic gel-thermal reduction process

Abstract

The organic gel-thermal reduction process was used for the preparation of ferromagnetic metal Ni, Co and Fe fine fibers from the raw materials of citric acid, lactic acid and metal salts. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermo-gravimetric/differential scanning calorimetry and scanning electron microscopy. The results show that spinnability of gel largely depends on molecular structure of metal-carboxylate complex that is a linear-type structure formed in the gel. As a result, the gels exhibit a good spinnability. Metal Ni, Co and Fe fine fibers are featured with diameters of around 1 μm and a high aspect ratio up to 1 × 10⁶.

Keywords

ferromagnetic metal fiber / organic gel / thermal reduction / spinnability

References

[1] ChungD. D. L.. Materials for electromagnetic interference shielding[J]. Journal of Materials Engineering and Performance, 2000, 9(3): 350-354

[2] LiY., ShenG.-z., XuZ.. Development of radar absorbing fibers in composites[J]. Advanced Ceramics, 2005, 1: 24-29

[3] ZhaoZ.-s., ZhangX.-c., NieY., et al.. Microwave magnetic properties of polycrystalline iron fiber absorbing materials[J]. J Magnetic Materials and Devices, 2000, 31(1): 18-20

[4] ShuiX. P., ChungD. D. L.. Submicron diameter nickel filaments and their polymer-matrix composites[J]. Journal of Materials Science, 2000, 35(7): 1773-1785

[5] CHOU K S, REN C Y, LO C T. Method of synthesizing nickel fibers and the nickel fibers so prepared. US 6375703B1[P]. 2002.

[6] NieY., ZhaoZ.-s., HeH.-hui.. Polycrystalline iron fibers prepared by pyrolysis of carbonyl by introducing magnetic field[J]. J Huazhong University of Science and Technology, 2001, 29(7): 75-77

[7] ZhengG.-q., NiS.-y., ZhengH.-j., et al.. Preparation of copper nano-wires by template synthesis method[J]. Journal of Central South University of Technology, 2004, 11(4): 371-374

[8] TsaiM. T.. Preparation and crystallization of forsterite fibrous gels[J]. Journal of the European Ceramic Society, 2003, 23: 1283-1291

[9] HodgsonS. N. B., ShenX., SaleF. R.. Preparation of alkaline earth carbonates and oxides by EDTA-gel method[J]. Journal of Materials Science, 2000, 35: 5275-5282

[10] LiW., ChengH.. Synthesis and characterization of Cu-Cr-O nanocomposites[J]. Journal of Central South University of Technology, 2007, 14(3): 291-295

[11] HodgsonS. N. B., ShenX., SaleF. R.. Electrophoretic deposition of alkaline earth-EDTA complexe[J]. Journal of Materials Science, 2002, 37: 4018-4028

[12] JingM., ShenX., ShenY.. Preparation of nanometer nickel oxide by the citrate-gel process[J]. Journal of Inorganic Materials, 2004, 19(2): 289-294

[13] TimothyJ. S., SatishiC. B. M.. Speciation of aqueous Ni(II)-carboxylate and Ni(II)-fulvicacid solutions: Combined ATR-FTIR and XAFS analysis[J]. Geochim Cosmochim Acta, 2004, 68(17): 3441-3458

[14] MARINOVIC V, DESPIC A R. Hydrogen evolution from solution of citric acids[J]. Journal of Electroanalytical Chemistry, 1997(431): 127–132.

[15] HouF., XuT.-x., YinY.-xin.. Preparing process of nanocrystalline thin film of perovskite-type complex oxide by ISG method[J]. Journal of Tianjin University, 2000, 33(3): 397-400

[16] WangX.-rong.. Photochromism of ferric citrate complex and determination of citric acid[J]. Chinese Journal of Analytical Chemistry, 1997, 25(2): 165-167

[17] WuK. H., YuC. H., ChangY. C., et al.. Effect of pH on the formation and combustion process of sol-gel auto-combustion derived NiZn ferrite/SiO₂ composites[J]. Journal of Solid State Chemistry, 2004, 177: 4119-4125