Soft Magnetic Alloy Surface Layer for High-Permeability Withstand Voltage
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Solution Overview
Problem
Existing magnetic devices face a trade-off between high packing rate of magnetic material, which increases relative permeability but decreases withstand voltage and m value, leading to instability in voltage variation.
Innovation Solution
A soft magnetic alloy with a surface layer having a specific distribution of Co/(Fe+Co) concentrations, including local minimum and maximum points, is used to enhance withstand voltage and m value while maintaining high relative permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the packing rate of magnetic material is increased to improve relative permeability, then the relative permeability is improved, but the withstand voltage decreases
Solution Approach 1:
The invention applies local quality by creating a surface layer with non-uniform Co concentration distribution (featuring local minimum and maximum points) rather than a homogeneous composition. This localized compositional variation optimizes the balance between withstand voltage and relative permeability at different regions of the magnetic powder particle, resolving the contradiction by allowing high packing rate while maintaining adequate insulation through the differentiated surface layer structure.
Solution Approach 2:
The invention uses composite materials by combining Fe-Co soft magnetic alloy with a surface layer containing oxide phase and specific element M (Si, Cr, or Al). This composite structure integrates the high permeability characteristics of the Fe-Co alloy with the insulation properties of the oxide-containing surface layer, enabling simultaneous achievement of high relative permeability and adequate withstand voltage.
2Reliability
If the packing rate of magnetic material is increased to improve relative permeability, then the relative permeability is improved, but the m value (degree of variation in withstand voltage) decreases
Solution Approach 1:
The non-uniform Co concentration distribution in the surface layer (with local minimum and maximum points) creates differentiated regions that stabilize the overall withstand voltage characteristics. The local minimum points provide insulation zones while the local maximum points maintain magnetic properties, reducing variation across the particle population and stabilizing the m value even at high packing rates.
3Quantity of substance
If the number of contact points between magnetic particles is increased to improve packing rate, then the packing rate is improved, but the withstand voltage decreases
Solution Approach 1:
The invention changes the compositional parameters of the surface layer by controlling the Co concentration distribution (with local minimum and maximum points) and incorporating oxide phase with specific element M. This parameter modification enhances the insulation capability at particle contact points, allowing increased packing rate without the usual degradation in withstand voltage.
Data Source
AI summary
A soft magnetic alloy includes a main body and a surface layer. The main body has a soft magnetic alloy composition including Fe and Co. The surface layer is located on a surface side of the main body. A ratio of Co concentration to a sum of Co concentration and Fe concentration in the surface layer is Co/(Fe+Co). A distribution of Co/(Fe+Co) in a thickness direction of the surface layer includes a local minimum point and one or more local maximum points.