Composite Magnetic Core Composition for Formable High-Inductance Coils
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Solution Overview
Problem
Magnetic cores for high-current inductors and reactors face challenges in improving formability, reducing crack generation, and maintaining inductance performance due to high hardness materials, which complicates the manufacturing process and limits their efficiency.
Innovation Solution
A magnetic core composed of a mixture of a first powder with lower hardness (100 HV to 250 HV) and a second powder with higher hardness (400 HV to 1000 HV), where the first powder constitutes 40% to 60% of the total volume, allowing for improved formability and reduced crack generation through a simple molding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high hardness magnetic core material is used to improve inductance performance and stable permeability, then inductance performance is improved, but formability deteriorates and manufacturing becomes difficult
Solution Approach 1:
The patent uses a composite magnetic core material consisting of FeSiAl alloy powder (50-80 wt%, Vickers hardness 500-1000) combined with pure iron powder (20-50 wt%, Vickers hardness 100-200). This composite structure allows the core to achieve both high inductance performance from the FeSiAl alloy and improved formability from the softer pure iron powder, resolving the contradiction between performance and manufacturability.
2Ease of manufacture
If binder and lubricant content is increased to improve formability, then formability is improved, but core density decreases limiting inductance performance
Solution Approach 1:
The patent optimizes the volume ratio of pure iron powder to FeSiAl alloy powder to 20-50 vol%, which allows achieving good formability with minimal binder and lubricant content (3-8 wt%). This parameter optimization ensures that the magnetic core maintains high density and excellent inductance performance while being easily formable through conventional molding processes.
3Ease of manufacture
If pure iron powder with low hardness is used to improve formability, then formability is improved, but inductance performance is limited
Solution Approach 1:
The patent creates a composite material system where pure iron powder (20-50 wt%, Vickers hardness 100-200) is combined with FeSiAl alloy powder (50-80 wt%, Vickers hardness 500-1000). The pure iron powder provides excellent formability and fills voids between harder particles, while the FeSiAl alloy powder contributes high permeability and stable magnetic properties, achieving both good formability and high inductance performance simultaneously.
4Reliability
If FeSiAl alloy powder with high hardness is used to increase inductance, then inductance performance is improved, but crack generation increases during manufacturing
Solution Approach 1:
The patent uses pure iron powder as an intermediary material that mediates between the hard FeSiAl alloy particles during the molding process. The softer pure iron powder acts as a buffer that absorbs mechanical stress and prevents direct contact between hard particles, thereby reducing crack generation while maintaining high inductance performance from the FeSiAl alloy content.
Data Source
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AI summary
An embodiment provides a magnetic core comprising a first powder and a second powder, wherein the hardness of the first powder is lower than that of the second powder, and the volume of the first powder is 40% to 60% with respect to the combined volume of the first powder and the second powder.