| Project/Area Number |
09450248
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | Doshisha University |
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Principal Investigator |
HIROTA Ken Faculty of Engineering, Doshisha University, Associate Professor, 工学部, 助教授 (30238414)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Osamu Faculty of Engineering, Doshisha University, Professor, 工学部, 教授 (40097861)
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| Project Period (FY) |
1997 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥12,100,000 (Direct Cost: ¥12,100,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1998: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1997: ¥7,100,000 (Direct Cost: ¥7,100,000)
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| Keywords | Mn-Zn ferrite / low-temperature sintering / additives / B_2O_3 (boron oxide) / lithium silicate glass / Super-Sendust / Mg-ferrite / Spark plasma sintering / 傾斜機能材料 / 微小X線回折 / 残留応力 / 磁性材料 / アグネシウムフェライト / センダスト / Ni-Zn-フェライト / Mn-Zn-フェライト / ガラス |
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| Research Abstract |
The present study is based on two parts : one deals with the development of low-temperature sintering Mn-Zn ferrite with additives and the other is concerned with metal/oxide composite materials. Highly sinterable Mn-Zn ferrite powder consisting of submicrometer-size particles (〜0.18μm) with structural distortion has been prepared by grinding a coprecipitated powder with a media agitation mill. Dense pure Mn-Zn ferrites (>98% of theoretical) can be fabricated by heating at 900℃ in a nitrogen atmosphere. They show magnetic and electric properties in which their permeability μ and electric resistivity ρ are 520-635 and 0.8-1.6Ω・m, respectively. These properties have been further improved by adding a small amount of lithium borosilicate glass ; especially, high values of μ=1015 and ρ=474Ω・m are achieved in ferrites (900℃/12h) with 0.1wt% glass addition. The microstructures consist of large grains (〜35μm) with high resistive layers at grain boundaries.
Dense composite materials (98.6% of theoretical) consisting of Super-Sendust (86.5Fe-6Si-4Al-3.5Ni wt%) and MgFe_2O_4 (75/25 vol%) have been fabricated by spark plasma sintering in air for 5 min at 850℃ and 130 MPa. They exhibit a high saturation magnetization density B_5 of 1.2 T and high electrical resistivity ρ of 1×10^<-2>Ω・m. Permeabilities μ>1000 at 1 kHz are obtained. Fine ferrite grains (〜0.6 μm) are located at the boundaries of the large spherical grains of Super Sendust (〜30 μm).
Furthermore, continuously graded Super・Sendust/Mg・ferrite materials have been fabricated and their properties are under investigation.
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