Soft Magnetic Powder Composition for Stable High-Frequency Permeability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing soft magnetic powders face challenges in achieving low coercive force, density, and DC superimposition characteristics due to oxidation and anisotropy, leading to reduced operational stability and permeability.
Innovation Solution
A soft magnetic powder with a composition of FexCuaNbb(Si1-y(B1-zCrz)y100-x-a-b, optimized for particle size and crystallite diameter, is mixed with a binder and compacted to form a molded body, ensuring low coercive force and high permeability, with a reduction rate in permeability of 3.0% or less between 1 MHz and 100 MHz frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If heat treatment is performed to reduce anisotropy and defects, then coercive force decreases, but oxidation occurs causing decrease in green compact density and DC superimposition characteristics
Solution Approach 1:
The patent applies parameter changes by precisely controlling heat treatment temperature (500-650°C) and duration to achieve the optimal balance between reducing coercive force through anisotropy reduction and preventing oxidation that would harm operational stability. This controlled thermal parameter adjustment resolves the contradiction by finding the optimal processing window.
Solution Approach 2:
The patent uses composite material composition (Fe-Cu-Nb-Si-B-Cr alloy system) where chromium content (0.01-3.0 atomic%) provides oxidation resistance while the overall composition is optimized for low coercive force. The composite structure allows simultaneous achievement of magnetic softness and oxidation resistance.
2Object-affected harmful factors
If particle size is reduced to improve magnetic properties, then coercive force decreases, but manufacturing precision and density control become more difficult
Solution Approach 1:
The patent applies parameter changes by optimizing particle size within the range of 5.0-45.0 μm and controlling crystallite diameter (5.0-20.0 nm) through controlled heat treatment. This parameter optimization achieves low coercive force while maintaining adequate green compact density and manufacturing precision.
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 results in a magnetic element with excellent DC superimposition characteristics and operational stability, minimizing magnetic saturation and eddy current loss, while maintaining high permeability and saturation magnetic flux density.
Implementation Method 1
a heat treatment is performed in the production of the soft magnetic powder. By performing the heat treatment, it is possible to reduce various defects and anisotropy (stress-induced anisotropy) that are introduced during the production of the soft magnetic powder
Implementation Method 2
By performing the heat treatment, it is possible to reduce various defects and anisotropy (stress-induced anisotropy) that are introduced during the production of the soft magnetic powder
Implementation Method 3
an obtained mixture is press-molded at a pressure of 294.2 MPa (3 t/cm2) to obtain a ring-shaped first molded body
Implementation Method 4
a soft magnetic powder with a composition of FexCuaNbb(Si1-y(B1-zCrz)y)100-x-a-b in terms of atomic ratio
Implementation Method 5
a reduction rate d of permeability is 3.0% or less, as represented by the following equation: d=(μ1-μ100)/μ100×100
Data Source
AI summary
A soft magnetic powder includes: impurities and a composition represented by a composition formula FexCuaNbb(Si1-y(B1-zCrz)y)100-x-a-b [a, b, x, y, and z satisfy 0.3≤a≤2.0, 2.0≤b≤4.0, 75.5≤x≤79.5, 0.55≤y≤0.91, and 0.015≤z≤0.185]. The soft magnetic powder has an average particle diameter of 5.0 μm or more and 45.0 μm or less, and has a crystallite diameter of 5.0 nm or more and 20.0 nm or less, as measured by an X-ray diffraction method, and a reduction rate d of permeability is 3.0% or less, as represented by the following equation:d=<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[LeftBracketingBar]"</annotation></semantics>μ1-μ100<semantics definitionURL="">❘<annotation encoding="Mathematica">"\[RightBracketingBar]"</annotation></semantics>/μ1×100in the above equation, μ1 is permeability measured at a frequency of 1 MHz, and μ100 is permeability measured at a frequency of 100 MHz.