Formation of (001) Fiber Texture in Iron Powder and its Effect on Magnetic Properties and Crystal Orientation of the Powder Compact

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 plateletshaped 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.

Crystallographic Texture and Applications of Pure Cu Formed by Shot Peening

“…Motozuka et al investigated the microstructural changes caused in Fe particles with bcc crystal structure by ball milling. [15][16][17] Ball milling is an SPD process and it induces a huge strain by mixing Fe particles and hard particles with relatively large diameters. Their studies showed that the Fe particle shape changes from granular to platelet during ball milling, and the grains in the Fe particles are highly refined.…”