Multi-Layer Oxide Metal Magnetic Particles for Inductor Insulation
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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 heat treatment is required to prevent oxidation.
Innovation Solution
A metal magnetic particle with a multi-layer oxide structure formed by mixing Si and Fe alkoxides with alcohol, followed by hydrolysis, drying, and heat treatment in an oxidizing atmosphere to create specific oxide layers with controlled thickness and crystallinity, enhancing insulation and direct-current superposition characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer insulating film or oxide layer is formed on metal magnetic particles, then insulation properties are improved, but film uniformity is poor and dielectric breakdown occurs
Solution Approach 1:
The patent divides the insulating layer into multiple sub-layers (first insulating film, first oxide layer, second oxide layer, second insulating film) with different functions and compositions. Each layer addresses specific requirements: some layers provide baseline insulation, others provide uniformity, and still others prevent dielectric breakdown, collectively solving the contradiction between insulation reliability and film uniformity
Solution Approach 2:
The patent employs composite material structures combining different insulating materials (organic insulating films and oxide layers) with distinct properties. This composite approach allows each material to contribute its strengths - organic films provide good insulation and oxide layers provide uniformity and high-temperature stability - thereby achieving both reliable insulation and manufacturing precision
2Object-affected harmful factors
If heat treatment is performed at high temperature to prevent oxidation, then oxidation resistance is improved, but insulation reliability deteriorates due to oxide layer defects
Solution Approach 1:
The patent applies preliminary protective measures by forming multiple robust insulating layers and oxide layers before heat treatment. These pre-formed layers act as protective barriers that prevent oxidation during high-temperature processing while maintaining insulation reliability, eliminating the need to choose between oxidation resistance and insulation quality
Solution Approach 2:
The patent creates a cushioning protective structure with multiple insulating and oxide layers that absorb and distribute thermal stress during heat treatment. This multi-layer configuration prevents defect formation and maintains insulation reliability even when subjected to high-temperature conditions required for oxidation resistance
3Power
If metal magnetic particles with high saturation magnetic flux density are used, then inductor performance is improved, but insulation resistance decreases
Solution Approach 1:
The patent applies local quality enhancement by concentrating insulating materials specifically at the particle surfaces and interfaces where insulation is most critical. The multi-layer structure ensures that each local region has the appropriate insulating properties needed to handle the high power density generated by metal magnetic particles with high saturation magnetic flux density
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 high withstand voltage and reduced power loss in inductors, while allowing for high-temperature processing without oxidation issues.
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, wherein the oxide layer has a first oxide layer, a second oxide layer, and a third oxide layer from the alloy particle side. 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 Si content takes a local maximum value, the second oxide layer is a layer where Fe content takes a local maximum value, and the third oxide layer is a layer where Si content takes a local maximum value.