Multilayer Oxide-Coated Magnetic Material for Stable Insulation
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Solution Overview
Problem
Metal magnetic materials used in electronic components face challenges with insufficient electrical insulation properties due to difficulties in filling gaps between soft magnetic metal grains with glass, leading to instability and lower insulation performance.
Innovation Solution
A magnetic material comprising soft magnetic metal grains coated with a multilayer oxide film, including a crystalline Fe oxide layer, an amorphous Si oxide layer, and optionally additional oxide layers, which provides improved insulation properties when formed through specific heat treatment processes in reducing or oxidizing atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass is used to fill gaps between soft magnetic metal grains, then insulation properties are improved, but manufacturing difficulty increases and insulation stability deteriorates
Solution Approach 1:
The patent changes the material parameter from glass to oxide film, and changes the formation mechanism from gap-filling to surface-coating. This is achieved by controlling oxidation parameters (temperature, atmosphere, time) to form a uniform oxide film on the metal grain surfaces, which naturally provides insulation without requiring gap-filling operations.
Solution Approach 2:
The patent replaces the mechanical gap-filling process with a chemical oxidation process. Instead of physically forcing glass into gaps between grains, the invention uses controlled oxidation to form an insulating film on the grain surfaces, substituting a chemical mechanism for a mechanical one.
2Quantity of substance
If metal materials are used instead of ferrite, then saturated magnetic flux density is improved, but volume resistivity deteriorates
Solution Approach 1:
The patent creates a composite structure consisting of soft magnetic metal grains (Fe, Fe-Si, Fe-Ni, etc.) coated with an oxide film layer. This composite structure combines the high magnetic flux density of metal materials with the high resistivity of oxide materials, achieving both improved magnetic performance and insulation properties.
Solution Approach 2:
The patent applies different properties to different parts of the material: the inner metal grain core provides high magnetic flux density, while the outer oxide film layer provides high volume resistivity. This local differentiation of material properties allows simultaneous optimization of both magnetic and electrical characteristics.
3Reliability
If oxide coating is applied to soft magnetic metal grains, then volume resistivity is improved, but magnetic permeability may deteriorate
Solution Approach 1:
The patent optimizes oxidation parameters (temperature, time, atmosphere composition) to control oxide film thickness and composition. By maintaining the oxide layer thickness within a specific range and controlling its composition, the invention achieves high resistivity while minimizing the negative impact on 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 multilayer oxide film enhances insulation properties and maintains magnetic permeability, offering stable and high-frequency performance while reducing resistivity deterioration, thus addressing the limitations of traditional ferrite materials.
Implementation Method 1
a second oxide layer of amorphous nature containing Si
Implementation Method 2
maintains magnetic permeability, offering stable and high-frequency performance
Data Source
AI summary
A magnetic material includes a soft magnetic metal grain containing Fe, and a multilayer oxide film covering the surfaces of the soft magnetic metal grain. The multilayer oxide film has a first oxide layer of crystalline nature containing Fe, and a second oxide layer of amorphous nature containing Si. In an embodiment, the silicon oxide film of amorphous nature is formed by dripping, divided into multiple sessions, a treatment solution containing TEOS (tetraethoxy silane), ethanol, and water into a mixed solution containing the soft magnetic metal grain, ethanol, and ammonia water, to mix the solutions.