Metal powder and method for producing metal powder

The CVD production of Fe-Si-Cr alloy powders with controlled particle size distribution and oxide coating addresses the issue of high core loss in miniaturized inductors, enhancing magnetic properties and reducing eddy current and hysteresis losses.

JP7870871B1Active Publication Date: 2026-06-05JFE MINERAL CO LTD
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
JFE MINERAL CO LTD
Filing Date
2025-08-08
Publication Date
2026-06-05

AI Technical Summary

Technical Problem

Conventional methods for producing metal powders for inductors result in high eddy current and hysteresis losses due to improper particle size distribution, leading to increased core loss and reduced magnetic properties, especially in miniaturized inductors operating at high frequencies.

Method used

A method involving CVD production of Fe-Si-Cr alloy powders with controlled particle size distribution, specifically defined by D50, D99, and D10, and surface oxide coating to minimize coarse particles, achieving a particle size range of 0.15 μm ≤ A ≤ 1.50 μm, B ≤ 2.27 × A + 0.57, and C ≥ 0.60 × A - 0.06, thereby reducing eddy current and hysteresis losses.

Benefits of technology

The controlled particle size and oxide-coated Fe-Si-Cr alloy powders exhibit improved magnetic properties with low core loss, suitable for compacted magnetic cores in miniaturized inductors, maintaining low coercivity and high saturation magnetization.

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Abstract

This invention provides a metal powder that forms a compacted material suitable for use as a magnetic core for inductors, offering low core loss and excellent magnetic properties, making it smaller than conventional inductors. [Solution] This metal powder is an Fe-Si-Cr system containing Si: 1.00%~10.00%, Cr: 0.10%~5.00%, O (oxygen): 0.10%~5.00% by mass concentration, with the remainder being Fe and unavoidable impurities. It has a metal oxide film on its surface, and when the number-based primary particle diameters D50 obtained from SEM measurement are A (μm), D99 is B (μm), and D10 is C (μm), the following conditions apply: 0.15 μm ≤ A ≤ 1.50 μm, B ≤ 2.27 × A + 0.57, and C ≥ 0.60 × A - 0.06. Furthermore, when the number-based primary particle diameter D90 is D (μm), it is preferable that D ≤ 2.03 × A + 0.20. Using this, a magnetic core for an inductor with low core loss can be obtained.
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