| Project/Area Number |
17360332
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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 |
Composite materials/Physical properties
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| Research Institution | Doshisha University |
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Principal Investigator |
HIROTA Ken Doshisha University, Faculty of Engineering, Professor (30238414)
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| Co-Investigator(Kenkyū-buntansha) |
KATO Masaki Doshisha University, Faculty of Engineering, Associate Professor (90271006)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥14,750,000 (Direct Cost: ¥14,300,000、Indirect Cost: ¥450,000)
Fiscal Year 2007: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2006: ¥4,600,000 (Direct Cost: ¥4,600,000)
Fiscal Year 2005: ¥8,200,000 (Direct Cost: ¥8,200,000)
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| Keywords | Composite materials. physical properties / Electronic and electric materials / Magnetic properties / Nano-structured materials / Ceramics / Interfaces |
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| Research Abstract |
With aiming at developing new bulk magnetic materials having both high saturation magnetization density and high magnetic permeability for high-frequency electric applications, fabrication of MgFe_2O_4/Fe-Ni alloy bulk nano-composites, in which Fe-Ni grains (〜5μm in diameter) are fully surrounded with thin MgFe_2O_4layer (〜0.3μm in thick), has been tried: the former metal grains have high saturation magnetization density and the latter has high electric resistivity.
The first stage, the best chemical compositions of MgFe_2O_4 have been investigated. Mg(Fe_<1-x>Mn_x)_2O_4 solid solution ferrites were prepared using both conventional solid reactions and sol-gel process, and their magnetic properties were measured precisely ; x=0.2 composition gave the best data. The second stage, plastic deformation of Mg(Fe_<1-x>Mn_x)_2O_4 ferrites were evaluated at temperature 1200 to 1350℃ in air.
Finally MgFe_2O_4/Fe-Ni alloy bulk composites has been tried by adopting high-pressure sintering two powder
… More
s: Composite Powder I and Composite Powder II . The former was prepared as follows; fine MgO particle-coated Fe-Ni powders were heat-treated under various oxygen partial pressures at 600°and 700℃. The latter was fine MgO+a-Fe_2O_3 mixed powder particles-coated Fe-Ni powders. For the composite powders, two sintering processes were tried; i.e., pulsed-electric current pressure sintering PECPS (800℃/30MPa/3min) or HIP (950°-1250℃/196MPa/2h). Phase identification by XRD and SEM observation revealed that dense microstructure consisting of two phases (spinel MgFe_2O_4 and Fe-Ni alloy) was attained from the combination of composite powders II, PECPS and a re-oxidation process. However, other process resulted in formation of Wusteit phase of Mg_<1-x>Fe_xO and FeO in addition to Fe-Ni due to highly reductive atmosphere during the sintering. Thus obtained composite materials consisting two phases showed good magnetic properties at room temperature as expected from their compositions and microstructures: saturation magnetization density B_s of 1.20 T, and permeabilityμ〜15-30 at 1 MHz, and a Curie point above 460℃. Less
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