Flaky Magnetic Powder Composition for High-Frequency Response
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional magnetic flaky powders, such as those made from Fe—Si—Al and Fe—Si—Cr alloys, are limited in their ability to maintain high saturation magnetization and frequency response above 200 MHz, making them unsuitable for high-frequency applications in electronic devices.
Innovation Solution
A flaky powder composition with specific ranges of C (1.5-3.0%), Cr (10-20%), and N (0.03-0.30%) is developed, along with a production process that includes heat treatments to achieve an average particle diameter of 200 μm or less, an average thickness of 5 μm or less, and an average aspect ratio of 5 or more, resulting in a saturation magnetization exceeding 1.0 T and a frequency response of 200 MHz or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional flaky powder (Fe-Si-Al or Fe-Si-Cr alloy) is used, then saturation magnetization can be maintained at 1.0 T or higher, but the frequency response is limited to 20 MHz or 50 MHz respectively, unable to reach 200 MHz
Solution Approach 1:
The invention changes the chemical composition parameters of the flaky powder by adding specific amounts of C (1.5-3.0 mass%), Cr (10-20 mass%), and N (0.03-0.30 mass%). This parameter change transforms the material properties, enabling the frequency response to reach 200 MHz or higher while maintaining saturation magnetization above 1.0 T, thus resolving the contradiction between frequency response and magnetization maintenance.
2Reliability
If flaky powder with higher saturation magnetization (Fe-Si-Cr alloy, 1.2 T) is used, then magnetization performance improves, but the frequency response only reaches 50 MHz at most, still insufficient for high-frequency applications
Solution Approach 1:
The invention creates a composite alloy system by combining Fe, Si, Cr, C, and N elements in specific proportions. The composite structure leverages the high magnetization of Fe-Si-Cr while the added C and N elements modify the microstructure and magnetic properties, enabling simultaneous achievement of high saturation magnetization (above 1.0 T) and high frequency response (200 MHz or higher).
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 resulting magnetic sheets exhibit improved high-frequency performance, with a frequency response of 200 MHz or more and a saturation magnetization above 1.0 T, enabling their use in thin, high-frequency applications while maintaining DC superposition characteristics and coercive force.
Implementation Method 1
a saturation magnetization exceeding 1.0 T
Implementation Method 2
giving superior electromagnetic absorptive properties even at small thickness
Data Source
AI summary
A flaky powder for high frequency application is provided, wherein the flaky powder contains 1.5 to 3.0 mass % C, 10 to 20 mass % Cr, 0.03 to 0.30 mass % N, and the balance being Fe and incidental impurities, and has an average particle diameter of 200 μm or less, an average thickness of 5 μm or less, an average aspect ratio of 5 or more, a saturation magnetization of more than 1.0 T, and a frequency (FR) of 200 MHz or more at which tan δ reaches 0.1. Based on the flaky powder, a novel magnetic flaky metal powder having a saturation magnetization exceeding 1.0 T and exhibiting a high FR of 200 MHz or more, and magnetic sheets including the magnetic flaky metal powder are provided.