Fe-Rich Magnetic Base Body With Si Oxide Insulating Surface
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Solution Overview
Problem
Magnetic base bodies with high Fe content face challenges in achieving an insulating surface without surface treatments like pickling or polishing, which can damage the material and complicate manufacturing, while existing solutions with FeCrAl alloy particles have lower saturation magnetic flux density and magnetic permeability.
Innovation Solution
A magnetic base body with a main body of metal magnetic particles having 98.5 wt% or more Fe content, where an oxide phase containing Si binds the particles, and an insulating film is formed on the surface during manufacturing, using a method involving mixing with a resin composition containing silsesquioxane or siloxane and thermally treating in an oxygen-rich atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal magnetic particles with high Fe content are used to achieve high magnetic permeability, then magnetic properties are improved, but a conductive oxide layer forms on the surface during manufacturing
Solution Approach 1:
Silicon acts as an intermediary element that modifies the oxidation behavior of Fe particles. During thermal treatment, Si preferentially oxidizes to form SiO2 on the particle surfaces, creating an insulating barrier that prevents Fe oxidation and subsequent conductive layer formation, while maintaining high Fe content (98.5 wt% or more) for excellent magnetic properties
Solution Approach 2:
The invention changes the chemical composition parameters by adding Si to the metal magnetic particles, transforming them from pure Fe particles to Fe-Si composite particles. This compositional change fundamentally alters the oxidation characteristics during thermal treatment, enabling insulating surface layer formation while preserving high magnetic permeability through maintained high Fe content
2Reliability
If surface treatment methods like pickling or polishing are used to remove the conductive layer, then insulating property is improved, but the magnetic base body may be chemically or mechanically damaged and manufacturing complexity increases
Solution Approach 1:
The invention performs preliminary action by adding Si to the metal magnetic particles before thermal treatment. This pre-positioning of Si ensures that during subsequent thermal treatment, SiO2 forms on the particle surfaces first, creating an insulating barrier that prevents conductive layer formation. This preliminary compositional adjustment eliminates the need for post-manufacturing surface treatment steps
Solution Approach 2:
The invention converts the potentially harmful effect of thermal treatment (which could form conductive Fe oxide layers) into a beneficial outcome. By adding Si, the thermal treatment process now produces insulating SiO2 layers instead of conductive Fe oxide, transforming a harmful process into a useful surface treatment that simultaneously provides insulation and protects the magnetic particles
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
This approach provides a highly insulating surface for magnetic base bodies with high Fe content without the need for surface treatments, maintaining high magnetic properties and preventing conductive layer formation, thus enhancing the filling rate and reducing eddy current loss.
Implementation Method 1
an insulating film is formed on the surface during manufacturing, using a method involving mixing with a resin composition containing silsesquioxane or siloxane and thermally treating in an oxygen-rich atmosphere
Implementation Method 2
The thermal treatment can form an oxide phase on the surface of the metal magnetic particles, and the oxide phase is used to bind the metal magnetic particles together
Data Source
AI summary
A magnetic base body relating to one embodiment of the present invention includes a main body and an oxide film formed on the surface of the main body. The main body includes an oxide phase containing Si and a plurality of metal magnetic particles bound via the oxide phase. In the metal magnetic particles, Fe accounts for 98.5 wt % or more. When an XRD diffraction pattern of the magnetic base body is observed, a ratio Ia/Ib is 10 or more where Ia denotes an integrated intensity of peaks derived from the (220) plane of Fe2O3 and Ib denotes an integrated intensity of peaks derived from the (104) plane of Fe3O4.