Kaizo Monma1, Takeo Sata2 and Kunio Onodera2
1Department of Metallurgy, Faculty of Engineering, Tohoku University, Sendai
It was found recently by the writers that the columnar crystal structure of the Alnico alloy can be obtained by zone melting and the crystal orientation method, based on a steep temperature gradient and a low solidification rate. This study was carried out in order to improve zone melting and the crystal orientation method. The results may be summarized as follows:
The temperature gradient at the solid-liquid interface is increased from 100°C/cm to 150°C/cm by water cooling on the solidificated part. The effects of the cooling condition which is shown by the distance between the water surface and the high frequency heating coil and the travelling rate on the macrostructure and magnetic properties have been tested. The exprimental results show that when a suitable water cooling condition is chosen, the macrostructure of Alnico magnet of the columnar crystal structure and parallel to rod axis can be obtained at a travelling rate higher than in the case of air cooling by zone melting and the crystal orientation method.
Please do not copy without permission.