Soft Magnetic Powder Coating for Low Eddy-Current Core Compaction
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Solution Overview
Problem
Existing soft magnetic material powders face challenges in achieving high magnetic permeability and electric resistance due to issues with fluidity in compaction molding, crack generation in organic films, and density limitations, which result in increased eddy-current loss.
Innovation Solution
A soft magnetic material powder comprising Fe-based soft magnetic material particles with a surface insulating film containing inorganic oxide and a water-soluble polymer, which enhances magnetic permeability and electric resistance by reducing stress in compression molding and maintaining high electric resistance through the insulating film and binder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin inorganic film is formed on the surface of metal magnetic powder, then electric resistance is improved, but fluidity in powder compaction molding deteriorates and fine cracks are generated
Solution Approach 1:
The patent applies composite materials by combining inorganic oxide particles (for electric resistance) with organic binder particles (for fluidity and crack prevention) to form a dual-component coating on the magnetic powder surface. This composite structure allows the inorganic film to provide high electric resistance while the organic component maintains powder fluidity and prevents crack generation during compaction molding.
Solution Approach 2:
The patent changes the parameters of the insulating film by controlling the particle size distribution of both inorganic oxide and organic binder, as well as their weight ratio. By optimizing these parameters (inorganic oxide 0.1-10 wt%, organic binder 0.1-5 wt%, specific particle size ranges), the film achieves sufficient electric resistance while maintaining adequate fluidity for compaction molding without generating fine cracks.
2Strength
If mineral is added to form insulating film, then film strength is improved and cracks are prevented, but thin film formation is inhibited and magnetic permeability is not sufficiently increased
Solution Approach 1:
The patent uses composite materials by combining inorganic oxide particles with organic binder particles in specific proportions. The organic binder provides film strength and crack prevention, while the inorganic oxide provides the necessary electric resistance. This composite approach allows thin film formation (maintaining magnetic permeability) while ensuring sufficient film strength to prevent cracks during handling and molding.
Solution Approach 2:
The patent applies local quality by creating a heterogeneous coating structure where inorganic oxide particles and organic binder particles are distributed in specific patterns and proportions on the magnetic powder surface. The organic binder provides localized strength and flexibility to prevent cracks, while inorganic oxide particles provide localized electric resistance, allowing thin overall film thickness that preserves magnetic permeability.
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 achieves a magnetic core with sufficient density, high magnetic permeability, and low eddy-current loss, maintaining high electric resistance and withstand voltage, suitable for applications in electronic components.
Implementation Method 1
the insulating film contains an inorganic oxide and a water soluble polymer
Implementation Method 2
by compression molding
Data Source
AI summary
A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.