US-12624430-B2 - Iron alloy particle and method for producing iron alloy particle

Abstract

The iron alloy particle is a particle including an iron alloy. The particle includes multiple mixed-phase particles, each including nanocrystals of 10 nm or more and 100 nm or less (i.e., from 10 nm to 100 nm) in crystallite size and an amorphous phase; and a grain boundary layer between the mixed-phase particles. Also, the iron alloy has a composition containing Fe, Si, P, B, C, and Cu.

Inventors

• Manabu Nakano

Assignees

• MURATA MANUFACTURING CO., LTD.

Dates

Publication Date

20260512

Application Date

20230407

Priority Date

20180323

Claims (2)

1. 1 . A method for producing iron alloy particles, comprising: applying a shearing process to an amorphous material comprising an iron alloy that includes Fe, Si, P, B, C, and Cu to plastically deform the amorphous material into particles and introduce a grain boundary layer into the particles; and applying a heat treatment to the particles with the grain boundary layer to precipitate, in the particles, nanocrystals of from 10 nm to 100 nm in crystallite size, wherein the shearing process is performed with a high-speed rotary grinder, and a rotor of the high-speed rotary grinder has a circumferential speed of 40 m/s or greater.
2. 2 . The method for producing iron alloy particles according to claim 1 , wherein the shearing process is performed on an amorphous alloy ribbon comprising the iron alloy.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Divisional of U.S. patent application Ser. No. 17/017,478, filed Sep. 10, 2020, which claims benefit of priority to International Patent Application No. PCT/JP2018/045959, filed Dec. 13, 2018, and to Japanese Patent Application No. 2018-056447, filed Mar. 23, 2018, the entire contents of each are incorporated herein by reference. BACKGROUND Technical Field The present disclosure relates to an iron alloy particle and a method for producing iron alloy particles. Background Art Conventionally, iron, silicon steel, and the like have been used as soft magnetic materials for use in various reactors, motors, transformers, and the like. These materials have high magnetic flux densities, but have high crystal magnetic anisotropy and thus have large hystereses. Thus, the magnetic parts obtained with the use of these materials have the problem of increasing the losses. To address such a problem, Japanese Patent Application Laid-Open No. 2013-67863 discloses a soft magnetic alloy powder represented by composition formula: Fe100-x-yCuxBy (in atomic %, 1<x<2, 10≤y≤20), including a structure in which crystal particles that have a body-centered cubic structure, of 60 nm or less in average particle size, are dispersed in a volume fraction of 30% or more in an amorphous matrix. SUMMARY The disclosure in Japanese Patent Application Laid-Open No. 2013-67863 describes achieving the effect of having a high saturation magnetic flux density and excellent soft magnetic characteristics. The disclosure in Japanese Patent Application Laid-Open No. 2013-67863, however, has the problem of inadequate high frequency characteristics. Accordingly, the present disclosure provides an iron alloy particle that has a high saturation magnetic flux density and favorable high frequency characteristics. The present disclosure also provides a method for producing the iron alloy particle. The iron alloy particle according to the present disclosure is a particle including an iron alloy, the particle includes multiple mixed-phase particles, each including nanocrystals of 10 nm or more and 100 nm or less (i.e., from 10 nm to 100 nm) in crystallite size and an amorphous phase; and a grain boundary layer between the mixed-phase particles, and the iron alloy has a composition containing Fe, Si, P, B, C, and Cu. In the iron alloy particle according to the present disclosure, the grain boundary layer preferably has a thickness of 200 nm or less. The method for producing iron alloy particles according to the present disclosure includes the steps of applying a shearing process to an amorphous material including an iron alloy that has a composition containing Fe, Si, P, B, C, and Cu to plastically deform the amorphous material into particles and introduce a grain boundary layer into the particles; and applying a heat treatment to the particles with the grain boundary layer to deposit, in the particles, nanocrystals of 10 nm or more and 100 nm or less (i.e., from 10 nm to 100 nm) in crystallite size. In the method for producing iron alloy particles according to the present disclosure, the shearing process is preferably performed with a high-speed rotary grinder, and a rotor of the high-speed rotary grinder preferably has a circumferential speed of 40 m/s or more. In the method for producing iron alloy particles according to the present disclosure, the shearing process is preferably performed for an amorphous alloy ribbon including an iron alloy. According to the present disclosure, an iron alloy particle can be provided which has a high saturation magnetic flux density and favorable high frequency characteristics. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view schematically illustrating an example of an iron alloy particle according to the present disclosure; and FIG. 2 is an enlarged view of a part of the iron alloy particle shown in FIG. 1. DETAILED DESCRIPTION An iron alloy particle according to the present disclosure will be described below. However, the present disclosure is not to be considered limited to the following configurations, but can be applied with changes appropriately made without changing the scope of the present disclosure. It is to be noted that the present disclosure also encompasses combinations of two or more individual desirable configurations according to the present disclosure as described below. [Iron Alloy Particle] FIG. 1 is a sectional view schematically illustrating an example of an iron alloy particle according to the present disclosure. The iron alloy particle 1 shown in FIG. 1 is a soft magnetic particle made of an iron alloy. The iron alloy particle 1 has one particle composed of multiple mixed-phase particles 10, with a grain boundary layer 20 between the mixed-phase particles 10. FIG. 2 is an enlarged view of a part of the iron alloy particle shown in FIG. 1. As shown in FIG. 2, the mixed-phase particle 10 includes nanocrystals 11 and an amorphous pha