Fe-Based Nanocrystalline Alloy Core Space Factor for 100 kHz Permeability

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Solution Overview

Problem

There is a demand for improved magnetic permeability in high frequency bands, particularly at 100 kHz, which conventional Fe-based nanocrystalline alloy cores are unable to meet.

Innovation Solution

An Fe-based nanocrystalline alloy core wound with a ribbon having a thickness of 11 µm to 14 µm and a space factor of 73% or higher, with specific surface roughness and profile characteristics, is developed. The manufacturing method involves winding an Fe-based amorphous alloy ribbon and heating it to crystallize the alloy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional Fe-based nanocrystalline alloy cores are used, then the device size can be reduced, but the magnetic permeability in high frequency bands (particularly at 100 kHz) is insufficient

Engineering Contradiction:
Improvemagnetic permeabilityVSAvoidperformance at high frequency
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the physical parameters of the alloy ribbon by controlling the thickness within 11-14 μm and managing the space factor at 73% or higher. These parameter changes enable the core to achieve magnetic permeability of 32,000 or higher at 100 kHz, resolving the contradiction between device size reduction and high-frequency performance.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If the ribbon thickness is reduced to decrease core size, then the device can be miniaturized, but the magnetic permeability and space factor deteriorate

Engineering Contradiction:
Improvecore sizeVSAvoidmagnetic permeability
Core Design Contradiction:
Volume of moving objectVSQuantity of substance

Solution Approach 1:

The patent identifies an optimal thickness range of 11-14 μm that balances size reduction with magnetic performance. Within this range, the core achieves high magnetic permeability (≥32,000 at 100 kHz) while maintaining a compact form factor, resolving the contradiction between miniaturization and performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies specific surface roughness characteristics (Rp ≥ 1.2 μm, Rv ≤ 3.7 μm) to the roll surface of the ribbon to optimize magnetic properties. This local quality control enhances magnetic permeability while maintaining the reduced core size, addressing the contradiction between compact dimensions and high performance.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If the space factor is increased to improve magnetic permeability, then the magnetic performance improves, but the manufacturing precision and surface quality become more difficult to control

Engineering Contradiction:
Improvemagnetic permeabilityVSAvoidsurface roughness control
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent specifies precise surface roughness parameters (Rp ≥ 1.2 μm, Rv ≤ 3.7 μm, Ra ≤ 0.6 μm) that enable high space factor (≥73%) while maintaining manufacturability. These controlled parameters achieve magnetic permeability of 32,000 or higher at 100 kHz without compromising manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The resulting Fe-based nanocrystalline alloy core achieves a magnetic permeability of 32,000 or higher at 100 kHz, surpassing conventional cores and enabling improved performance in electronic devices.

Implementation Method 1

a step of heating the core precursor

Methodology Applied
Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP4542587A1Fe-based nanocrystalline alloy core and manufacturing method of fe-based nanocrystalline alloy core
Publication Date: 2025.04.23 PROTERIAL LTD
  • EP4542587A1 patent drawingFigure 1
  • EP4542587A1 patent drawingFigure 2
  • EP4542587A1 patent drawingFigure 3

AI summary

An Fe-based nanocrystalline alloy core including a core wound with an Fe-based nanocrystalline alloy ribbon, the Fe-based nanocrystalline alloy ribbon having a thickness of greater than or equal to 11 µm and less than 14 µm, and a space factor of greater than or equal to 73% as measured in accordance with IEC 60404-8-11:2018.