Ferromagnetic Powder Composition Coating for Core Loss Reduction
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Solution Overview
Problem
Current soft magnetic powder compositions face challenges in achieving improved core loss characteristics and resistivity, particularly at high frequencies, where eddy current losses are significant, and maintaining mechanical strength and permeability without detrimental effects on other properties.
Innovation Solution
A ferromagnetic powder composition with soft magnetic iron-based core particles coated with a phosphorus-based inorganic insulating layer and partially covered with hydrolysable metal-organic compounds, such as alkyl alkoxy silanes or silsesquioxanes, along with a lubricant, is compacted using high pressure and optimized heat treatment to enhance resistivity and reduce core losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If finer particle size powders are used to reduce eddy current losses at high frequencies, then electrical resistivity improves, but mechanical strength and permeability deteriorate
Solution Approach 1:
The patent applies composite materials by combining iron-based soft magnetic particles with a multi-layer coating system consisting of phosphorous-based inorganic insulating layer and hydrolysable metal-organic compound layer. This composite structure allows the use of finer particles (50-150 μm) for reduced eddy current losses while the robust coating system maintains mechanical strength and electrical resistivity, resolving the contradiction between particle size reduction and mechanical property preservation.
2Loss of energy
If conventional insulation coatings are used to achieve electrical resistivity, then eddy current losses are reduced, but mechanical strength and ejection behavior deteriorate
Solution Approach 1:
The patent applies parameter changes by transitioning from conventional insulation coatings to hydrolysable metal-organic compounds (silanes, siloxanes, silsesquioxanes) with specific chemical properties. These compounds undergo hydrolysis and condensation to form strong cross-linked networks that provide both electrical insulation for eddy current reduction and enhanced mechanical strength for improved green body integrity and ejection behavior.
Solution Approach 2:
The patent applies composite materials by combining the phosphorous-based inorganic insulating layer with the hydrolysable metal-organic compound layer. This composite coating system provides synergistic effects where the inorganic layer ensures electrical insulation and the organic-inorganic hybrid layer provides mechanical reinforcement, simultaneously addressing eddy current loss reduction and mechanical strength requirements.
3Ease of manufacture
If more lubricant is added to improve ejection behavior, then manufacturing ease improves, but electrical resistivity and core loss characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the lubricant content to a controlled range (0.1-0.5 wt%) and selecting specific lubricant types that minimize negative impacts on electrical resistivity. The hydrolysable metal-organic compound coating system compensates for the presence of lubricant by providing enhanced electrical insulation, allowing sufficient lubricant for ejection while maintaining core loss characteristics.
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 results in soft magnetic components with high resistivity, low core losses, and improved mechanical strength, maintaining high permeability and induction while minimizing hysteresis and eddy current losses, even at high frequencies.
Implementation Method 1
at least one metal-organic compound is hydrolysable and is selected from alkyl alkoxy silanes, alkyl alkoxy (poly)siloxanes, alkyl alkoxy silsesquioxanes
Implementation Method 2
the surface of the core particles is provided with at least one phosphorus-based inorganic insulating layer
Implementation Method 3
at least one metal-organic compound is hydrolysable and is selected from alkyl alkoxy silanes, alkyl alkoxy (poly)siloxanes, alkyl alkoxy silsesquioxanes
Data Source
AI summary
A ferromagnetic powder composition including soft magnetic iron-based core particles, wherein the surface of the core particles is provided with at least one phosphorus-based inorganic insulating layer and then at least partially covered with metal-organic compound(s), wherein the total amount of metal-organic compound(s) is between 0.005 and 0.05% by weight of the powder composition, and wherein the powder composition further includes a lubricant. Further, a process for producing the composition and a method for the manufacturing of soft magnetic composite components prepared from the composition, as well as the obtained component.