Iron-Based Soft Magnetic Composite Powder for Inductor Cores
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Solution Overview
Problem
Existing soft magnetic composite materials face challenges in achieving high resistivity and low core losses, especially at high frequencies, and require organic binding agents that can decompose under heat treatment, limiting their temperature stability and performance in power electronics applications.
Innovation Solution
A new iron-based composite powder with a phosphorous containing layer and a second layer comprising alkaline silicate and talc phyllosilicates is used, eliminating the need for organic binding agents, allowing for higher heat treatment temperatures and improved magnetic properties without compromising strength or stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic binding agents are used in soft magnetic composite materials, then the material can be compacted and formed into components, but the organic agents decompose under heat treatment limiting temperature stability and performance
Solution Approach 1:
The invention removes organic binding agents from the soft magnetic composite material and replaces them entirely with inorganic coating layers (phosphorous-containing layer and silicate layer). This extraction of the harmful organic component eliminates decomposition issues during heat treatment while maintaining the necessary compaction and forming capabilities through the powder metallurgy process.
Solution Approach 2:
The invention changes the chemical composition parameters of the coating layers by specifying phosphorous content (0.01-0.15 wt%) and silicate content (0.1-0.9 wt%), along with controlled heating rates (10-100°C/min) and heat treatment temperatures (400-700°C). These parameter changes enable achieving both good compaction properties and high temperature stability without organic decomposition.
2Speed
If high frequencies are used in inductor applications, then the inductor can operate at higher frequencies above 2 kHz, but core losses increase due to eddy current losses proportional to the square of frequency
Solution Approach 1:
The invention changes the electrical resistivity parameter of the soft magnetic composite material by incorporating phosphorous and silicate coatings, which increase the bulk electrical resistivity. This parameter change reduces eddy current losses (which are proportional to the square of frequency) and enables efficient operation at high frequencies above 2 kHz with low core losses.
3Stability of the object's composition
If low maximum relative permeability is used in inductor cores, then the inductor has good DC-bias performance and linear characteristic, but the inductance value decreases
Solution Approach 1:
The invention uses a composite material structure with iron-based core particles coated with phosphorous-containing and silicate-containing layers. This composite structure enables achieving both low maximum relative permeability (for good DC-bias and linearity) and sufficient inductance value by optimizing the core particle properties and coating composition, allowing efficient operation across a wide current range.
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 achieves high resistivity, low core losses, and enhanced temperature stability, enabling efficient operation at frequencies above 2 kHz with improved saturation flux density and DC-bias performance, facilitating core downsizing and reduced hysterisis losses.
Implementation Method 1
it is especially required to reduce the eddy current loss and still maintaining a low level of hysterisis losses. This implies that it is desired to increase the resistivity of magnetic cores
Implementation Method 2
Ferromagnetic- or iron- core inductors use a magnetic core made of a ferromagnetic or ferrimagnetic material such as iron or ferrite to increase the inductance of a coil by several thousand by increasing the magnetic field, due to the higher permeability of the core material
Implementation Method 3
A varying current will create a varying magnetic field which will induce a voltage opposing the change of current that created it. The electromagnetic force (EMF) which opposes the change in current is measured in volts(V) and is related to the inductance according to the formula
Implementation Method 4
the present invention relates to an iron-based soft magnetic composite powder, the core particles thereof being coated with a carefully selected coating rendering the material properties suitable for production of inductors through compaction of the powder followed by a heat treating process
Data Source
AI summary
The present invention concerns a composite iron-based powder suitable for soft magnetic applications such as inductor cores. The present invention also concerns a method for producing a soft magnetic component and the component produced by the method.