Cu-Segregated Soft Magnetic Powder for High-Current Core Stability
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Solution Overview
Problem
Existing soft magnetic powders face challenges in maintaining excellent soft magnetism under high electric currents, particularly in achieving low core loss and preventing magnetic saturation, as they struggle to balance coercive force and saturation magnetic flux density effectively.
Innovation Solution
A soft magnetic powder with a composition of FexCuaNbb(Si1-yBy)100-x-a-b, where Cu is segregated deeper than 30 nm and has a maximum concentration exceeding 6.0 at%, combined with crystal grains of 1.0 nm to 30.0 nm in diameter, optimizing the content of Fe, Cu, Nb, Si, and B to achieve low coercive force and high saturation magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Cu is uniformly distributed in the soft magnetic powder, then the saturation magnetic flux density can be maintained, but the coercive force increases and magnetic saturation occurs under high electric current
Solution Approach 1:
The patent applies local quality by creating a non-uniform Cu distribution where Cu is segregated in the inner region (deeper than 30 nm from surface) with concentration exceeding 6.0 at%, while the surface region maintains lower Cu concentration. This local differentiation allows the inner region to provide high saturation magnetic flux density while the surface region maintains low coercive force, resolving the contradiction between these two magnetic properties under high electric current conditions.
2Loss of energy
If fine crystal grains are contained to reduce core loss at high frequency, then the coercive force decreases, but the saturation magnetic flux density is reduced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Cu concentration parameter in different regions of the particle. By setting Cu concentration to exceed 6.0 at% in the inner region and controlling the depth of segregation to be deeper than 30 nm from the surface, the patent optimizes the balance between coercive force and saturation magnetic flux density, achieving both low core loss and high saturation magnetic flux density simultaneously.
3Reliability
If the particle size is reduced to prevent magnetic saturation under high electric current, then the core loss decreases, but the manufacturing precision and Cu segregation control become more difficult
Solution Approach 1:
The patent applies preliminary action by pre-establishing the Cu segregation structure during the manufacturing process, with Cu segregated deeper than 30 nm from the surface with maximum concentration exceeding 6.0 at%. This preliminary structuring ensures that the magnetic properties are optimized before the product is put into service, making the manufacturing process more controllable and reproducible despite the fine particle size requirements.
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 powder magnetic core with low core loss and reduced likelihood of magnetic saturation even at high electric currents, enabling miniaturization and increased output efficiency.
Implementation Method 1
includes a Cu segregated portion in which Cu is segregated, the Cu segregated portion is present at a position deeper than 30 nm from a surface of the particle, and a maximum Cu concentration in the Cu segregated portion exceeds 6.0 at %
Data Source
AI summary
A soft magnetic powder including particles having a composition represented by FexCuaNbb(Si1-yBy)100-x-a-b [provided that a, b, and x are each a number whose unit is at % and satisfy 0.3≤a≤2.0, 2.0≤b≤4.0, and 73.0≤x≤79.5, respectively, and y is a number satisfying f(x)≤y≤0.99, in which f(x)=(4×10−34)x17.56], wherein the particle contains a crystal grain having a grain diameter of 1.0 nm or more and 30.0 nm or less, and includes a Cu segregated portion in which Cu is segregated, the Cu segregated portion is present at a position deeper than 30 nm from a surface of the particle, and a maximum Cu concentration in the Cu segregated portion exceeds 6.0 at %.