Magnetic Core Powder Blending for High DC Superimposition
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Solution Overview
Problem
Coil devices require higher DC superimposition characteristics and smaller size with improved magnetic properties for applications in high-frequency switching power supplies, which existing magnetic core powders fail to adequately provide.
Innovation Solution
A magnetic core powder composed of a granular Fe-based crystalline metal material and an Fe-based amorphous metal material, with specific particle size distributions and compositions, is mixed to enhance permeability and DC superimposition characteristics, and a method for producing this powder using atomizing techniques is developed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If amorphous alloy powder and crystalline alloy powder with different compositions are mixed to reduce core loss, then magnetic core performance is improved, but particle size distribution control becomes more complex
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size parameters d50A (0.5-7.0 μm) for crystalline powder and d50B (>15.0 μm) for amorphous powder, along with their mixing ratios. This systematic parameter optimization achieves the dual benefit of reduced core loss and simplified manufacturing, as the specific particle size ranges enable good powder flowability and molding characteristics without requiring complex distribution control
Solution Approach 2:
The patent uses composite materials by combining amorphous alloy powder and crystalline alloy powder with different compositions and particle size characteristics. This composite approach leverages the advantages of both material types: amorphous powder provides high permeability while crystalline powder contributes to low core loss, achieving superior overall magnetic core performance
2Volume of moving object
If magnetic cores are made smaller for compact coil devices, then device size is reduced, but DC superimposition characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size parameters d50A (0.5-7.0 μm) and d50B (>15.0 μm) along with their mixing ratios. This systematic parameter optimization achieves high permeability that enables compact magnetic core design while maintaining excellent DC superimposition characteristics, resolving the contradiction between miniaturization and performance
Solution Approach 2:
The patent applies local quality by creating a bimodal particle size distribution where fine crystalline particles (d50A: 0.5-7.0 μm) fill the gaps between larger amorphous particles (d50B: >15.0 μm). This localized arrangement optimizes both packing density for compactness and magnetic flux distribution for superior DC superimposition characteristics
3Reliability
If higher permeability is achieved by using finer particles, then magnetic properties are improved, but powder flowability and molding characteristics worsen
Solution Approach 1:
The patent applies parameter changes by establishing specific particle size ranges: d50A of 0.5-7.0 μm for crystalline powder and d50B of >15.0 μm for amorphous powder. This parameter optimization achieves high magnetic properties through the fine crystalline particles while the coarser amorphous particles provide good powder flowability and molding characteristics, resolving the contradiction between magnetic performance and manufacturability
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 magnetic core powder enables the formation of magnetic cores with high permeability and improved DC superimposition characteristics, suitable for smaller coil devices operating at high frequencies, effectively addressing the need for enhanced magnetic properties.
Implementation Method 1
the particle size d50A of the granular powder A at a cumulative frequency of 50% by volume being 0.5 μm or more and 7.0 μm or less, and the particle size d50B of the granular powder B at a cumulative frequency of 50% by volume being more than 15.0 μm, in a cumulative distribution curve showing the relation between a particle size and a cumulative frequency from the smaller particle size side, which is determined by a laser diffraction method
Data Source
AI summary
A magnetic core powder including granular powder A of Fe-based, magnetic, crystalline metal material and granular powder B of Fe-based, magnetic, amorphous metal material; the particle size d50A of granular powder A at a cumulative frequency of 50 volume % being 0.5 μm or more and 7.0 μm or less, and the particle size d50B of granular powder B at a cumulative frequency of 50 volume % being more than 15.0 μm, in a cumulative distribution curve showing the relation between particle size and cumulative frequency from the smaller particle size side, determined by a laser diffraction method; the magnetic core powder meeting (d90M−d10M)/d50M of 1.6 or more and 6.0 or less, d10M being a particle size at a cumulative frequency of 10 volume %, d50M being a particle size at a cumulative frequency of 50 volume %, and d90M being a particle size at a cumulative frequency of 90 volume %.