Abstract
Soft magnetic powder compacts can suppress eddy current loss compared to conventional laminated cores. However, the compacts accompany greater hysteresis losses because the easy magnetization axes are not controlled in powders. In this study, a novel soft magnetic compact was prepared from a platelet-shaped iron powder with well-controlled easy magnetization axes and its effects on magnetic properties and crystal orientation of the compact were investigated. Such platelet iron powder was produced using a ball-milling process. During milling, the iron powder was subjected to the deformation, resulting in the shape change to the platelet. Simultaneously, a (001) fiber texture was formed preferentially, as it is characteristic of the deformed bcc metal. The powder was then compacted into a toroidal shape. The platelet surface of the powder was oriented so as to become parallel to the toroidal direction. Consequently, the easy magnetization axis, which lies along the platelet surface, was also oriented to the toroidal direction. The toroidal compact prepared in this way exhibited excellent magnetic properties. For example, the permeability was approximately 2.4 times higher than that of the compact prepared from a conventional iron powder.
