Fe-Si Magnetic Particle Oxide Layer for Uniform Insulation
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Solution Overview
Problem
Existing methods for improving insulation properties of metal magnetic particles, such as coating with glass or forming an oxide layer, face challenges like non-uniform film formation, potential defects in the oxide layer, and limitations in high-temperature heat treatment.
Innovation Solution
A metal magnetic particle with an oxide layer comprising a first, second, and third oxide layer, all containing Si, is formed on an alloy particle containing Fe and Si. The oxide layers are created through a process involving Si alkoxide and alcohol, followed by heat treatment in an oxidizing atmosphere, to achieve specific thicknesses and crystallinity for enhanced insulation and magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating film such as glass is coated on the surface of a metal magnetic particle, then insulation properties are improved, but uniform film formation becomes difficult and thin film portions become start points of dielectric breakdown
Solution Approach 1:
The patent changes the chemical composition parameters of the insulating layer by specifying it contains SiO2, SiO, Si, B2O3, B, P2O5, P, Al2O3, Al, and Cr2O3 in specific ranges. This compositional parameter change enables formation of a uniform insulating layer with appropriate thickness while maintaining good insulation properties and avoiding dielectric breakdown.
Solution Approach 2:
The patent uses a composite insulating layer containing multiple oxide components (SiO2, SiO, B2O3, Al2O3, Cr2O3) rather than a single material. This composite structure provides both uniform film formation and excellent insulation properties, resolving the contradiction between reliability 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 proposed solution achieves excellent insulation properties and direct-current superposition characteristics, improving the reliability and performance of metal magnetic particles and inductors.
Implementation Method 1
forming a coating film forming particle formed with a coating film containing silicon oxide by hydrolyzing and drying the Si alkoxide
Implementation Method 2
forming an oxide layer on the surface of the alloy particle by performing heat treatment on the coating film forming particle in an oxidizing atmosphere
Data Source
AI summary
A metal magnetic particle provided with an oxide layer on a surface of an alloy particle containing Fe and Si. The oxide layer has a first oxide layer, a second oxide layer, and a third oxide layer from a side of the alloy particle. All of the first oxide layer, the second oxide layer, and the third oxide layer contain Si. Also, in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the first oxide layer is a layer having Fe content smaller than Si content in the alloy particle, the second oxide layer is a layer having Fe content larger than the Si content in the alloy particle, and the third oxide layer is a layer having Fe content smaller than the Si content in the alloy particle.