1992 Fiscal Year Final Research Report Summary
| Project/Area Number |
03555165
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学・無機材料工学
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| Research Institution | Nagoaka University of Technology |
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Principal Investigator |
MATSUSITA Kazumasa Nagaoka University of Technology Department of Chemistry, Professor., 工学部, 教授 (80024610)
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| Co-Investigator(Kenkyū-buntansha) |
NITTA Atsumi Nagaoka Plant, ALPS Electric Co., LTd, 長岡工場
SATO Ryuji Nagaoka University of Technology Department of Chemistry, Research Associate, 工学部, 助手 (60226024)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Magunetic head / Adhesion glass / Sendust / Ferrite / Lead silicate glass / Interface reaction / Standard free energy |
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| Research Abstract |
Electric and magnetic devices have been becoming smaller and smaller in recent year. Most of these devices are composed of many materials. Oxode glasses are extensively used to form the gap of magnetic heads. It has been well known that the properties of composite magnetic devices are strongly influenced by the interface condition. Therefore, it is important to reveal the mechanism of the interface reactions thoroughly for developing those devices. The purpose of this study is to reveal the mechanisms of interface reaction between magnetic materials and oxide glasses.
The interface reactions between Fe-Al-Si alloy (so-called SENDUST) and SiO_2-PbO binary systems were analyzed using X-ray diffraction, electron probe microanalysis and vibrating sample magnetometer methods. It is found that aluminum atoms in the alloy diffuse to the interface and dissolve into the glass melt as Al^<3+> ions, and at the same time, Pb^<2+>, Na^+ or H^+ ions in the melt are reduced. We concluded that the following redox reactions occurred at the interface between the alloy and oxide glasses when heated at high temperature.
3Pb^<2+>_<glass> + 2Al_<alloy> -> 3Pb + 2Al^<3+>_<glass>
3Na^+ + Al_<alloy> -> 3Na + Al^<3+>_<glass>
6H^+ + 2Al_<alloy> -> 3H_2 + 2Al^<3+>_<glass>
The same redox reactions occur at the interface in Fe-Ga-Si alloy.
Because the ionic radius of Ga^<3+> is the same as that of Al^<3+>.
It is well known that the viscosity of glasses containing Al_2O_3 becomes high with increasing the concentration of Al_2O_3 in the glass.
The viscosity of glass in the vicinity of interface becomes high because of diffusion of aluminum atom in the alloy and the chemical potential of aluminum atoms in the glass increases. As a result, the interface reactions are inhibited.
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