Fe-Si Magnetic Particle Oxide Layers for Insulation Reliability
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Solution Overview
Problem
Existing methods for improving insulation properties of metal magnetic particles, such as coating with insulating films or oxide layers, face challenges like non-uniform film formation, dielectric breakdown, and insufficient insulation reliability, particularly when high-temperature heat treatment is required to prevent oxidation.
Innovation Solution
A metal magnetic particle with a multi-layer oxide structure formed on an Fe-Si alloy surface, comprising a first, second, third, and fourth oxide layer, where each layer has a local maximum content of either Si or Fe, achieved through a process involving Si and Fe oxide film formation, hydrolysis, and heat treatment in an oxidizing atmosphere, resulting in enhanced insulation and direct-current superposition characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single insulating film is coated on metal magnetic particles, then insulation properties are improved, but film uniformity deteriorates leading to dielectric breakdown
Solution Approach 1:
The patent divides a single insulating film into multiple alternating oxide layers (Si oxide and Fe oxide layers) with different compositions. This segmentation allows each layer to form uniformly through controlled oxidation processes while the alternating structure prevents dielectric breakdown by distributing stress and preventing defect propagation across the entire insulation barrier.
Solution Approach 2:
The patent creates a composite insulating structure consisting of alternating Si oxide and Fe oxide layers. This composite material approach combines the advantages of different oxides: Si oxide provides excellent insulation properties while Fe oxide layers prevent excessive Si oxidation and contribute to structural stability. The composite structure achieves both high insulation reliability and uniform formation.
2Stability of the object's composition
If high-temperature heat treatment is performed to prevent oxidation, then oxidation resistance is improved, but insulation reliability deteriorates due to oxide layer defects
Solution Approach 1:
The patent performs preliminary oxidation of the metal magnetic particle surface before forming the final insulating oxide layers. This preliminary action creates a controlled oxide foundation that prevents uncontrolled oxidation during subsequent high-temperature heat treatment, thereby maintaining insulation reliability while achieving oxidation resistance through the protective alternating oxide structure.
Solution Approach 2:
The patent carefully controls oxidation parameters during the formation process, including oxygen partial pressure, temperature, and treatment time. By optimizing these parameters, the process forms uniform alternating Si oxide and Fe oxide layers without creating defects, achieving both oxidation resistance and insulation reliability simultaneously.
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 multi-layer oxide structure significantly improves insulation resistance and direct-current superposition characteristics, providing a metal magnetic particle and inductor with high withstand voltage and improved magnetic properties.
Implementation Method 1
forming a coating film forming particle formed with a coating film containing silicon oxide by hydrolyzing 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, a third oxide layer, and a fourth oxide layer. 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 where Fe content takes a local maximum value, the second oxide layer is a layer where Fe content takes a local maximum value, the third oxide layer is a layer where Si content takes a local maximum value, and the fourth oxide layer is a layer where Fe content takes a local maximum value.