高性能磁気ヘッド用ガラスの開発

近年来，电和磁装置已经变得越来越小。这些设备中的大多数由许多材料组成。氧化物玻璃广泛用于形成磁头的差距。众所周知，复合磁性器件的性能受界面条件的强烈影响。因此，深入揭示界面反应的机理对器件的研制具有重要意义。为了揭示磁性材料与氧化物玻璃之间的界面反应机理，本文采用X射线衍射、电子探针和振动样品磁强计等方法研究了Fe-Al-Si合金（SENDUST）与SiO_2-PbO二元体系的界面反应。研究发现，合金中的铝原子向界面扩散，以Al^3+离子的形式溶解到玻璃熔体中，同时熔体中的Pb^2+、Na^+或H^+离子被还原。结果表明，高温加热时，在合金与氧化物玻璃的界面上发生了如下氧化还原反应：3 Pb ^&lt;2+&gt;_<glass>+ 2Al_<alloy>-&gt; 3 Pb + 2Al^&lt;3+&gt;_<glass>3 Na ^+ + Al_<alloy>-&gt; 3 Na + Al^&lt;3+&gt;_<glass>6 H ^+ + 2Al_<alloy>-&gt; 3H_2 + 2Al^&lt;3+&gt;_。<glass>在Fe-Ga-Si合金中，由于Ga^&lt;3+&gt;和Al^&lt;3 +&gt;的离子半径相同，所以在界面上也发生了同样的氧化还原反应。由于铝原子在合金中的扩散，玻璃中铝原子的化学势增大，界面附近玻璃的粘度变高。结果，界面反应被抑制。

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.