Developments of Shock-Compaction Method Under Magnetic Field and of High Performance Magnets

磁场冲击压实方法及高性能磁体的研究进展

基本信息

批准号：
01850162
负责人：
KONDO Ken-ichi
金额：
$ 5.18万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B).
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01850162/
关键词：
Shock Compaction Permanent Magnet Nanocrystalline Materials Magnetic Field Sintering High Current Pulse High Speed Measurement Shock Wave 永久磁石希土類磁石

项目摘要

In 1989, an apparatus of shock compaction under magnetic fields were designed and constructed. Since the apparatus was furnished with a velocity-measuring system which was newly developed using optical fibres, high precision and high reproducibility were obtained in the measurements. The maximum velocity obtained were 1.9 km/s for a projectile of 10 g in weight by using gun powder of 60 g and were a capacity of 25 % higher than that designed. On the other hand, in the low velocity range, it was necessary to improve the powder chamber for stable operation. Magnetic field was probably high enough to saturate a magnetic flux in usual materials because of a high energy capacitor bank of 25 kJ.Ultrafine iron powder, which was supplied by Kantodenka, Co., Ltd., was used as a starting powder. Since the powder was needle-like and had a high aspect ratio of 10 to 30, we obtained only a low packing density of 32 % which led to increase shock temperature too much. A ultrasonic dispersion and sedimentation improved the density upto 41 % which led to compacts with density of 71 % by shock compaction. A multi-stage shock-compression technique using a complex impactor considerably suppressed shock temperature and provided good compacts with density of 92 %. It is necessary to increase more the pasking density in future by per-forming the powder under magnetic field. This technique was expected to improve magnetic properties.Microstructures of the compacts consisted of nanocrystalline particles without grain growth. We have, therefore, nanocrystalline metallic materials in prospect. In order to improve magnetic properties, however, further experimental investigations, such as surface treatments, effects of additives relations between grain boundaries and magnetic fields, and so on, are required.

1989年，设计和构造了磁场下的冲击压实设备。由于该设备配备了使用光纤新开发的速度测量系统，因此在测量中获得了高精度和高可重复性。通过使用60 g的枪粉，重量为10 g的弹丸获得的最大速度为1.9 km/s，容量比设计的容量高25％。另一方面，在低速范围内，有必要改善粉末室以进行稳定操作。由于高能电容器库为25 kJ.Ultrafine铁粉，磁场可能足够高，可以在通常的材料中饱和，该磁场由Kantodenka，Co.，Ltd。提供，用作起始粉末。由于粉末类似针状，高纵横比为10到30，因此我们仅获得了32％的低填料密度，从而导致休克温度过多。超声分散和沉淀提高了密度高达41％，这导致紧凑型由冲击压实的密度为71％。使用复杂撞击器的多阶段冲击压缩技术大大抑制了冲击温度，并提供了良好的契约，密度为92％。有必要通过在磁场下将粉末构成粉末来增加未来的Pasking密度。预计该技术将改善磁性性能。紧凑型的微结构由纳米晶体颗粒组成，没有晶粒生长。因此，我们在前景中具有纳米晶金属材料。但是，为了改善磁性特性，需要进一步的实验研究，例如表面处理，晶界和磁场之间添加剂关系的影响等等。