Insulating-Coated Soft Magnetic Powder for High-Frequency Core Loss Reduction
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Solution Overview
Problem
Existing soft magnetic powders, such as those described in JP-A-2016-15357, fail to adequately reduce core loss in high frequency bands above 1 MHz, limiting their effectiveness in modern communication devices that require improved magnetic performance.
Innovation Solution
An insulating material-coated soft magnetic powder is developed, featuring an Fe-based alloy with a specific particle size distribution and an insulating film, where the particle diameter D50 is between 0.1 μm and 3.0 μm, and the D90/D50 ratio is 2.00 or less, reducing eddy current losses by optimizing particle size and coating the Fe-based alloy soft magnetic powder with a silicon oxide or composite oxide insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If amorphous alloy powder with D50 of 5-20 μm and D90/D10 ratio of 3.3-6.5 is used, then filling property during compacting molding is improved and mechanical strength is increased, but core loss in high frequency band (1 MHz or more) cannot be sufficiently reduced
Solution Approach 1:
The patent changes the particle size parameters from D50=5-20 μm to D50=5-20 μm with D90/D10 ratio of 3.3-6.5, and applies insulating film coating to reduce eddy current loss while maintaining filling property and mechanical strength
Solution Approach 2:
The patent creates a composite structure by coating amorphous alloy powder particles with insulating films (such as silicon oxide, phosphorus oxide, or their combinations), forming a core-shell structure that reduces eddy current loss while maintaining the mechanical properties of the original powder
2Loss of energy
If particle size D50 is reduced to 0.1-3.0 μm with D90/D50 ratio of 2.00 or less, then core loss in high frequency band is reduced, but filling property during compacting molding may deteriorate
Solution Approach 1:
The patent optimizes particle size parameters to D50=0.1-3.0 μm with D90/D50 ratio of 2.00 or less, and combines this with insulating film coating to achieve both reduced core loss and maintained filling property through the composite structure
Solution Approach 2:
The insulating film coating provides local electrical insulation at particle surfaces, preventing eddy current formation between particles while maintaining the overall packing density and filling property of the powder mixture
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 solution effectively minimizes eddy current losses in high frequency bands, enhancing the magnetic properties and reducing core losses, thereby improving the performance of magnetic elements in electronic devices and moving bodies.
Implementation Method 1
a core loss in the high frequency band cannot be sufficiently reduced... effectively minimizes eddy current losses in high frequency bands
Implementation Method 2
an insulating film formation step of forming an insulating film with which a particle surface of the Fe-based alloy soft magnetic powder is coated
Data Source
AI summary
An insulating material-coated soft magnetic powder includes: an Fe-based alloy soft magnetic powder; and an insulating film with which a particle surface of the Fe-based alloy soft magnetic powder is coated. D50 is 0.1 μm or more and 3.0 μm or less where D50 is a particle diameter of the Fe-based alloy soft magnetic powder at which a cumulative frequency is 50% in a volume-based particle size distribution, and a ratio of D90/D50 is 2.00 or less where D90 is a particle diameter of the Fe-based alloy soft magnetic powder at which the cumulative frequency is 90% in the volume-based particle size distribution.