Soft Magnetic Powder Composition for High-Fluidity Dust Cores
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Solution Overview
Problem
The production of dust cores for electronic components faces challenges with soft magnetic materials having wide particle size distributions, leading to low fluidity and increased material loss, which decreases production efficiency and yield.
Innovation Solution
A soft magnetic material with a particle size frequency distribution having multiple peak tops, where the medium powder-particle substance has a particle size of 45 µm to 300 µm and an average circularity of 0.7 or more, ensuring high fluidity and reducing material loss by maintaining a wide particle size range without the need for uniform particle sizing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the particle size distribution of soft magnetic material is narrowed by classification to increase fluidity, then fluidity is improved, but material loss increases and yield decreases
Solution Approach 1:
The invention changes the particle size distribution parameters by specifying a multi-peaked distribution with controlled ratios between different size ranges. Instead of uniform classification, it maintains a wide distribution where D90/D10 ≤ 20.0, with specific peak area ratios (Aα≥0.25, Aβ≥0.20, Aγ≤0.15) that optimize both fluidity and material utilization without classification loss
Solution Approach 2:
The invention creates a composite particle size structure combining multiple particle size ranges (45-300 μm medium particles, 300-850 μm large particles, and <45 μm fine particles) in specific proportions. This composite approach allows each size range to contribute differently to fluidity while maintaining overall material efficiency and reducing the need for aggressive classification
2Quantity of substance
If granulated powder with larger target particle size is produced, then the amount of soft magnetic material used increases, but particle size uniformity decreases and fluidity worsens
Solution Approach 1:
The invention optimizes the particle size parameters by establishing specific distribution characteristics (D50≥200 μm, D90/D10≤20.0) and peak area ratios that allow larger overall material quantity while maintaining good fluidity. The multi-peaked distribution with controlled parameters ensures that increased material quantity does not compromise flow properties
3Loss of substance
If soft magnetic material with wide particle size distribution is used, then material loss decreases, but fluidity decreases causing uneven loading and lower production efficiency
Solution Approach 1:
The invention fine-tunes the particle size distribution parameters to achieve an optimal balance: maintaining wide distribution (D90/D10≤20.0) to reduce material loss while controlling the shape parameters (average circularity ≥0.70) and peak ratios to ensure sufficient fluidity for uniform loading and high production efficiency
Solution Approach 2:
The invention applies different quality requirements to different particle size ranges within the distribution. Medium particles (45-300 μm) with high circularity (≥0.70) provide the fluidity backbone, while large particles (300-850 μm) contribute to material utilization and fine particles (<45 μm) fill voids, creating local optimizations that collectively solve the contradiction
Data Source
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AI summary
A soft magnetic material (1) according to an aspect of the present invention includes a powder-particle substance (10) having a particle size frequency distribution (20) having a plurality of peak tops. The powder-particle substance (10) is an aggregate of composite particles (11) containing a plurality of soft magnetic metal particles (12) and includes a medium powder-particle substance in which the composite particles (11) have a particle size of 45 um or more and less than 300 µm, and the medium powder-particle substance has an average circularity of 0.7 or more.