Preparation of silica-coated ferrite nanoparticles for micro-wave absorber

微波吸收体用二氧化硅包覆铁氧体纳米粒子的制备

• 批准号: 12555218
• 负责人: WAKABAYASHI Katsuhiko
• 金额: $ 8.64万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12555218/
• 关键词: Silica-coated ferrite; Magnetite; Cobalt-ferrite; Zinc-ferrite; Microemulsion; ナノスケール; シリカ包接; フェライト; コバルト修飾マグネタイト

Ferrite materials, which possess highly permeable and insulating, are attracting growing interest, because they might be used at high frequencies as inductors for micro-magnetic devices or wave absorbers for EMI suppression.In this study, silica-coated ferrite nanoparticles (SiO_2-coated magnetite (Fe_3O_4), SiO_2-coated cobalt-ferrite (Co_xFe_<3-x>O_4) and SiO_2-coated zinc-ferrite (ZnxFe_<3-x>O_4) were prepared using a water-in-oil microemulsion consisting of water, polyoxyethylen (15) cetylether (surfactant) and cyclohexene (oil). After preparing Fe_3O_4 particles in the solution, an aqueous solution of cobalt chloride or zinc chloride (CoCl_2 or ZnCl_2) was added into the microemulsion containing Fe_3O_4 nanoparticles, and Co-Fe hydroxide complex or Zn-Fe hydroxide complex were formed on the surface of the Fe_3O_4 nanoparticles. TEOS and diluted NH_4OH solution were charged into the microemulsion, and subjected to hydrolysis to produce SiO_2.From TEM observations, a ferrite particl … More e was located nearly at the center of each spherical SiO_2 particle. The particle size of Fe_3O_4 and the thickness of the SiO_2 layer were very uniform and varied to within the range of 8.8 nm-13.4 nm and 7.0 nm-20.0 nm, respectively ; furthermore, the size distribution of the Fe_3O_4 particles was very narrow. As the Fe_3O_4 content increased from 3.6 wt% to 10.9 wt%, the saturation magnetization improved from 2.0 emu/g to 6.9 emu/g. Furthermore, the solid solution of Co ions and Zn ions into Fe_3O_4 to form Co_xFe_<3-x>O_4 and Zn_xFe_<3-x>O_4 nanoparticles during air calcination led to an increase in the magnetic properties of the SiO_2-coated ferrite nanoparticles. The coercivity of the SiO_2-coated Co_xFe_<3-x>O_4 nanoparticles increased with increasing amounts of added Co, obtaining a maximum value of 780 Oe around a Co/Fe ratio of 0.3-0.4. The saturation magnetization of the SiO_2-coated Co_xFe_<3-x>O_4 nanoparticles increased with increasing amounts of added Zn, and the maximum value was obtained around a Zn/Fe ratio of approximately 0.1. Less

铁氧体材料具有高渗透性和绝缘性，可作为微磁性器件的高频电感或抑制电磁干扰的吸波剂，正引起人们越来越多的关注。采用由水、聚氧乙烯（15）十六烷基醚（表面活性剂）和环己烯（油）组成的油包水微乳液制备了二氧化硅包覆铁氧体纳米粒子(二氧化硅包覆磁铁矿（Fe_3O_4）、二氧化硅包覆钴铁氧体（Co_xFe_<3-x bbb_o_4）和二氧化硅包覆锌铁氧体（ZnxFe_<3-x>O_4）。在溶液中制备Fe_3O_4颗粒后，在含有Fe_3O_4纳米颗粒的微乳液中加入氯化钴或氯化锌（CoCl_2或ZnCl_2）水溶液，在Fe_3O_4纳米颗粒表面形成Co-Fe氢氧配合物或Zn-Fe氢氧配合物。将TEOS和稀释的NH_4OH溶液充入微乳液中，水解生成SiO_2。TEM观察发现，每个SiO_2球形粒子的中心附近都有一个铁素体粒子。Fe_3O_4晶粒尺寸均匀，SiO_2层厚度变化范围分别为8.8 nm ~ 13.4 nm和7.0 nm ~ 20.0 nm；此外，Fe_3O_4颗粒的尺寸分布很窄。随着Fe_3O_4含量从3.6 wt%增加到10.9 wt%，饱和磁化强度从2.0 emu/g提高到6.9 emu/g。此外，空气煅烧过程中Co离子和Zn离子固溶到Fe_3O_4中，形成Co_xFe_<3-x>O_4和Zn_xFe_<3-x>O_4纳米颗粒，使sio_2包覆铁氧体纳米颗粒的磁性能得到提高。Co_xFe_<3-x>O_4纳米粒子的矫顽力随Co添加量的增加而增加，在Co/Fe比为0.3 ~ 0.4时达到最大值780 Oe。sio_2包覆的Co_xFe_<3-x>O_4纳米颗粒的饱和磁化强度随Zn添加量的增加而增加，在Zn/Fe比约为0.1时达到最大值。少

项目成果

T. Tago, R. Nagase, T. Hatsuta, M. Kishida and K. Wakabayashi: "Preparation of Silica-Coated Magnetite Nanoparticles Using Water-in-Oil Microemulsion"Proceedings of the Eighth International Conference on Ferrite. 763-765 (2000)

T. Tago、R. Nagase、T. Hatsuta、M. Kishida 和 K. Wakabayashi：“利用油包水微乳液制备二氧化硅包覆的磁铁矿纳米颗粒”第八届国际铁氧体会议论文集。

T.Tago, T.Hatsuta, R.Nagase, M.Kishida, K.Wakabayashi: "Synthesis of Silica-Coated Cobalt Ferrite Nanoparticles Using Water-in-Oil Microemulsion"Transactions of the Materials Research Society of Japan. 25. 877-880 (2000)

T.Tago、T.Hatsuta、R.Nagase、M.Kishida、K.Wakabayashi：“使用油包水微乳液合成二氧化硅包覆的钴铁氧体纳米颗粒”日本材料研究学会汇刊。

M. Kishida, T. Tago, T. Hatsuta and K. Wakabayashi: "Preparation of Silica-Coated Rhodium Nonoparticles Using Water-in-Oil Microemulsion"Chemistry Letters. 1108-1109 (2000)

M. Kishida、T. Tago、T. Hatsuta 和 K. Wakabayashi：“使用油包水微乳液制备二氧化硅包覆的铑纳米颗粒”化学快报。

T. Hanaoka, H. Hayashi, T. Tago, M. Kishida and K. Wakabayashi: "In situ immobilization of ultrafine particles synthesized in a water/oil microemulsion"Journal of Colloid and Interface Science. 235. 235-240 (2001)

T. Hanaoka、H. Hayashi、T. Tago、M. Kishida 和 K. Wakabayashi：“水/油微乳液中合成的超细颗粒的原位固定”胶体与界面科学杂志。

T.TAGO,R.NAGASE,T.HATSUTA,M.KISHIDA and K.WAKABAYASHI: "Preparation of Silica-Coated Magnetite Nanoparticles Using Water-in-Oil Microemulsion"Proc.of the 8^<th> International Conference on Ferrites. September. 2337 (2000)

T.TAGO，R.NAGASE，T.HATSUTA，M.KISHIDA 和 K.WAKABAYASHI：“使用油包水微乳液制备二氧化硅包覆的磁铁矿纳米粒子”第 8 届国际铁氧体会议论文集。