Abstract：FeSi powders were surface modified and coated with TEOS, CoCl2∙6H2O and FeCl3∙6H2O, which were used as raw materials to fabricate FeSi@SiO2@CoFe2O4 composite powders by chemical co-precipitation method. The effects of calcination temperature on the coating layer structure, magnetic properties and electromagnetic wave absorption properties of composite powders were systematically investigated. The results show that with the increase of calcination temperature from 500 ℃ to 800 ℃, CoFe2O4@SiO2 particles evenly were covered on the surface of FeSi powders gradually gather and grow up, which lead to the destruction of the local structure of the coating. The composite powders calcined at 600 ℃ have a uniform and dense SiO2@CoFe2O4 coating layer structure, high saturation magnetization (173.2 (A∙m2)/kg, high coercivity (3 047.8 A/m) and excellent electromagnetic wave absorption properties. All of the composite powders exhibit maximum reflection loss (RLmax) of (-53.5)-(-56.5) dB and effective bandwidths (RL≤-10 dB) of 4.64-5.68 GHz. Specially, the composite powders calcined at 600 ℃ achieve effective and strong absorption properties in a wide frequency band under thin thickness. They have three strong absorption peaks with the RLmax values of -56.5 dB (8.76 GHz, 2.78 mm), -49.2 dB (14.00 GHz, 2.11 mm) and -40.5 dB (15.28 GHz, 1.60 mm), and wide effective bandwidths with the effective bandwidths (RL≤-10 dB) of 4.80 GHz, 6.24 GHz and 3.44 GHz, respectively. The electromagnetic wave loss mechanism of the powder is excellent impedance matching characteristics, high electromagnetic wave attenuation constant, multiple dielectric relaxation process, multiple interface polarization, high magnetic loss and dielectric loss ability.
[1] DAI B Z, ZHAO B, XIE X.et al.Novel two-dimensional Ti3C2Tx MXenes/nano-carbon sphere hybrids for high- performance microwave absorption[J]. Journal of Materials Chemistry C, 2018, 6(21): 5690-5697. [2] SHAHZAD F, ALHABEB M, HATTER C B, et al.Electromagnetic interference shielding with 2D transition metal carbides (MXenes)[J]. Science, 2016, 353(6304): 1137-1140. [3] SUO Q T, XU B C, WANG J J, et al. Effect of high energy ball milling on electromagnetic properties of FeNi absorbing materials[C]// LIU L, YANG C, KE J. Advancesin Materials, Machinery, Electronics II. USA: American Instrument Physics, 2018, 1955: 020006-1-020006-6. [4] 刘渊, 吴晋瑞, 王莹. 羰基铁/NiLa0.02Fe1.98O4双层宽频吸波体的构建及实现[J]. 中国有色金属学报, 2020, 30(7): 1626-1633. LIU Yuan, WU Jingrui, WANG Ying.Preparation and design of carbonyl iron/NiLa0.02Fe1.98O4 double layer absorber[J]. The Chinese Journal of Nonferrous Metals, 2020, 30(7): 1626-1633. [5] ABBASI H, ANTUNES M, VELASCO JI.Recent advances in carbon-based polymer nanocomposites for electromagnetic interference shielding[J]. Progress in Materials Science, 2019, 103: 319-373. [6] ZHOU J, SHU X F, WANG Z C, et al.Hydrothermal synthesis of polyhedral FeCo alloys with enhanced electromagnetic absorption performances[J]. Journal of Alloys and Compounds, 2019, 794: 68-75. [7] YANG R, LIANG W, CHEN C, et al. Electromagnetic and microwave absorbing properties of raw and milled FeSiCr particles[J]. Journal of Applied Physics, 2014, 115(17): 17B536. [8] HUANG W B, TONG Z Y, LI W T, et al.Fabrication of flower-like ZnFe2O4@SiO2@C@NiO nanochains/reduced graphene oxides as a high-performance microwave absorber[J]. Journal of Alloys and Compounds, 2020, 849: 156658. [9] WEI Q W, PEI S F, QIAN X T, et al.Superhigh electromagnetic interference shielding of ultrathin aligned pristine graphene nanosheets Film[J]. Advanced Materials, 2020, 32(14): 1907411. [10] KUANG D T, HOU L Z, WANG S L, et al.Facile synthesis of Fe/Fe3C-C core-shell nanoparticles as a high-efficiency microwave absorber[J]. Applied Surface Science, 2019, 493: 1083-1089. [11] DUAN B F, ZHANG J N, WANG G W, et al.Microwave absorption properties of easy plane anisotropy Fe-Si powders with surface modification in the frequency range of 0.1-4 GHz[J]. Journal of Materials Science (Materials in Electronics), 2019, 30(14): 13810-13819. [12] LIU C, YUAN Y, JIANG J T, et al.Microwave absorption properties of FeSi flaky particles prepared via a ball-milling process[J]. Journal of Magnetism and Magnetic Materials, 2015, 395:152-158. [13] LIU L D, DUAN Y P, GUO J B, et al.Influence of particle size on the electromagnetic and microwave absorption properties of FeSi/paraffin composites[J]. Physica B-Condensed Matter, 2011, 406(11): 2261-2265. [14] HAN R, HAN X H, QIAO L, et al.Enhanced microwave absorption of ZnO-coated planar anisotropy carbonyl-iron particles in quasimicrowave frequency band[J]. Materials Chemistry and Physics, 2011, 128(3): 317-322. [15] ZHANG C K, JIANG J J, BIE S W, et al.Electromagnetic and microwave absorption properties of surface modified Fe-Si-Al flakes with nylon[J]. Journal of Alloys and Compounds, 2012, 527: 71-75. [16] LIU Y, LI R, JIA Y, et al.Effect of deposition temperature on SrFe12O19@carbonyl iron core-shell composites as high- performance microwave absorbers[J]. Chinese Physics B, 2020, 29(6): 067701. [17] ZHANG Y T, LIU C Y, PENG K S, et al.Synthesis of broad microwave absorption bandwidth Zr4+-Ni2+ ions gradient-substituted barium ferrite[J]. Ceramics International, 2020, 46(16): 25808-25816. [18] CHEN Q L, LI L Y, WANG Z L, et al.Synthesis and enhanced microwave absorption performance of CIP@SiO2@Mn0.6Zn0.4 Fe2O4 ferrite composites[J]. Journal of Alloys and Compounds, 2019, 779: 720-727. [19] ZHANG X M, JI G B, LIU W, et al.A novel Co/TiO2 nanocomposite derived from a metal organic framework: synthesis and efficient microwave absorption[J]. Journal of Materials Chemistry C, 2016,4(9): 1860-1870. [20] LIAO J J, GAO P Zo, XU L, et al.A study of morphological properties of SiO2 aerogels obtained at different temperatures[J]. Journal of Advanced Ceramics, 2018, 7(4): 307-316. [21] LIU G, WANG L Y, CHEN G M, et al.Enhanced electromagnetic absorption properties of carbon nanotubes and zinc oxide whisker microwave absorber[J]. Journal of Alloys and Compounds, 2012, 514: 183-188.
2021, Vol. 26 
