Magnetic Base Body Bonding for Stronger Insulated Coil Components
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Solution Overview
Problem
Existing magnetic base bodies for coil components face challenges in achieving high mechanical strength while maintaining insulation reliability, particularly due to the difficulty in heat treatment processes that prevent sintering of metal magnetic grains.
Innovation Solution
A magnetic base body comprising metal magnetic grains bonded by an amorphous mixture containing carbon and an oxide of elements like silicon, aluminum, chromium, magnesium, titanium, and zirconium, which inhibits crack growth and ensures insulation reliability through high electrical resistivity, with a carbon ratio in the bonding parts adjusted to maintain insulating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is performed at high temperature to bond oxide films on metal magnetic grains, then insulation reliability is improved, but metal magnetic grains sinter and mechanical strength deteriorates
Solution Approach 1:
A glass component is introduced as an intermediary material between metal magnetic grains during heat treatment. This glass component melts and forms a bonding part that bonds the oxide films on metal magnetic grains, preventing direct contact and sintering of the metal grains while enabling effective bonding at lower temperatures that preserve mechanical strength
Solution Approach 2:
The invention changes the heat treatment temperature parameter from high temperature (which causes sintering) to a lower temperature range (500-700°C) where the glass component can still melt and bond the oxide films effectively, thus preventing grain sintering while achieving insulation reliability
2Strength
If metal magnetic grains are bonded directly without oxide film coating, then mechanical strength is improved, but insulation reliability deteriorates
Solution Approach 1:
Oxide films are formed on the surface of metal magnetic grains as an intermediary insulating layer. These oxide films provide electrical insulation between adjacent metal grains, while the glass component bonding process ensures strong mechanical bonding without requiring direct metal-to-metal contact
Solution Approach 2:
The invention creates a composite structure consisting of metal magnetic grains coated with oxide films, bonded together by a glass-based bonding part. This composite approach combines the magnetic properties of metal grains with the insulating properties of oxide films and the bonding capabilities of glass material
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 solution effectively improves mechanical strength and insulation reliability of the magnetic base body, preventing sintering and maintaining insulating properties, as demonstrated by increased bending strength and volume resistivity in the magnetic base body.
Implementation Method 1
the bonding parts are constituted by an amorphous mixture containing carbon and an oxide of at least one element selected from silicon, aluminum, chromium, magnesium, titanium, and zirconium
Implementation Method 2
Since metal magnetic grains are low in insulating property, an art of coating the surface of metal magnetic grains with silicon oxide films, aluminum oxide films, or other insulating films is known
Implementation Method 3
heat treatment is performed at high temperature in Patent Literature 2. When subjected to heat treatment at high temperature, however, the metal magnetic grains will bond directly over the oxides (necking)
Data Source
AI summary
A method for manufacturing a coil component includes: providing multiple metal magnetic grains; preparing a magnetic body paste by mixing the multiple metal magnetic grains, a binder resin containing a resinate having at least one element selected from the group consisting of Si, Al, Cr, Mg, Ti, and Zr, and a solvent; forming a compact using the magnetic body paste; heat-treating the compact to form, on surfaces of the metal magnetic grains, bonding parts constituted by an amorphous oxide containing carbon and the at least one element, thereby forming a magnetic base body wherein the multiple metal magnetic grains are bonded via the bonding parts; forming a coil that includes a metal conductor; and forming external electrodes on surfaces of the magnetic base body and connecting end parts of the coil to the external electrodes, respectively.