| 摘要 |
PURPOSE:To obtain a remarkably long columnar crystal by a method wherein molten spinodal decomposition type permanent magnet alloy of Al-Ni-Co, etc. is poured into a heated mold provided with a chiller on its bottom, and when a permanent magnet is formed by restricting solidification in one direction, the chiller is cooled by dry ice or the like. CONSTITUTION:After spinodal decomposition type permanent magnet alloy of Al-Ni-Co, Fe-Cr-Co, etc. is melted, it is poured into a heat mold provided with a chiller on its bottom solidification of the melt is restricted in one direction, and while crystallization adjustment is operated, a columlar crystalline permanent magnet is formed. At this time, dry ice, liquid nitrogen or liquid carbon dioxide is used for cooling the chiller. By this, the temperature gradient in the melt in the neighborhood of the solid-liquid boundary becomes large, and it is possible to obtain a columnar crystal as long as 80-90mm, and the magnetic charactersitics of the permanent magnet are improved. |
