| Project/Area Number |
09650346
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
KITAMOTO Yoshitaka (Tokyo Institute of Technology, Faculty of Engineering, Research Associate), 工学部, 助手 (10272676)
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| Co-Investigator(Kenkyū-buntansha) |
ABE Masanori Tokyo Institute of Technology, Faculty of Engineering, Professor), 工学部, 教授 (70016624)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1998: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1997: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Ferrte Thin Fiim / Magnetite / Ferrite Plating / Polymer Microspheres / Ni-Zn Ferrite / Purification |
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| Research Abstract |
This report describes the ferrite plating using purified clean aqueous solutions to compress the formation of impurity particles, which are incorporated in plated films and degrade their microstructure and magnetic properties. To realize the ultra-clean solutions, 1) a reaction solution and an oxidizing one were prepared using ultrapure water and supplied through membrane filters of 0.1 mum in pore diameter, 2) an ammonia solution was supplied to keep a pH value during the reaction instead of CH_3COONH_4 that forms impurity particles by mixing with Fe^<2+> ions. Magnetite (Fe_3O_4) and Ni-Zn ferrite films were synthesized on glass substrates or polymer spheres.
The polymer microspheres with ferrite coatings are used as carrier particles for enzyme immunoassay. The ferrite coatings are necessary for collecting the particles using magnetic field. Thickness of the ferrite coatings is required to be equal or less than 50 nm to obtain a good dispersion performance in water. In methods without using the clean solution technique, continuous films with such thickness were not obtained due to large grains of around 100 nm, which were caused by incorporated impurity particles formed in the solution. In the new method, small grains of 10-20 nm were observed in the initial stage. When the layer thickness was 50 nm, the polymer particles were fully encapsulated with ferrite coatings, which have smooth surface and were composed of uniform and small grains. Mossbauer spectra showed that the coatings are composed of magnetite. The saturation magnetization was almost the same as the bulk value. The particles coated with 50 nm-thick magnetite exhibited the excellent dispersion performance in water and efficiency of magnetic separation by the magnetic field of 40 Oe. These performances were superior to those of the product in the market for enzyme immunoassay.
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