M-Type Ferrite Powder for Flexible GHz Absorbing Sheets
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Solution Overview
Problem
Existing electromagnetic wave absorbing sheets face challenges in maintaining flexibility and uniform physical properties when highly filled with ferrite powder, leading to difficulties in sheet preparation and reduced electromagnetic wave absorbing performance in the GHz band.
Innovation Solution
Optimizing the powder characteristics of M-type ferrite powder, including a compressed density of 3.00 g/cm3 or more and an average particle diameter of 0.50 to 3.0 μm, to reduce resin composition viscosity during melt-kneading and enhance fine dispersion of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filling amount of ferrite powder is increased to improve electromagnetic wave absorbing performance, then the electromagnetic wave absorbing performance is improved, but the flexibility of the sheet is significantly reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution of ferrite powder (D10: 0.3-1.0 μm, D50: 1.5-3.0 μm, D90: 4.0-6.0 μm) and controlling the volume ratio of fine particles (0.5 μm or less) to total particles at 10-40%. This controlled parameter optimization allows high filling amount while maintaining flexibility by preventing excessive viscosity increase and ensuring uniform dispersion.
2Reliability
If the filling amount of ferrite powder is increased to improve electromagnetic wave absorbing performance, then the electromagnetic wave absorbing performance is improved, but the viscosity of the resin composition during melt-kneading increases
Solution Approach 1:
The patent changes the particle size distribution parameters of ferrite powder, specifically controlling D10 to 0.3-1.0 μm, D50 to 1.5-3.0 μm, and D90 to 4.0-6.0 μm, with fine particles (0.5 μm or less) comprising 10-40% by volume. This parameter optimization reduces resin composition viscosity during melt-kneading by improving flow characteristics while maintaining high filling capability.
Solution Approach 2:
The patent segments the ferrite powder into different particle size ranges with specific volume ratios: fine particles (0.5 μm or less) at 10-40%, medium particles (0.5-2.0 μm) at 30-70%, and coarse particles (2.0-5.0 μm) at 10-30%. This segmentation prevents particle aggregation and ensures uniform dispersion, reducing viscosity increase during high filling amount processing.
3Reliability
If the filling amount of ferrite powder is increased to improve electromagnetic wave absorbing performance, then the electromagnetic wave absorbing performance is improved, but the uniformity of physical properties of the sheet is significantly reduced
Solution Approach 1:
The patent segments ferrite powder into three particle size ranges with controlled volume ratios: fine particles (0.5 μm or less) at 10-40%, medium particles (0.5-2.0 μm) at 30-70%, and coarse particles (2.0-5.0 μm) at 10-30%. This segmentation ensures uniform distribution throughout the sheet, preventing aggregation and maintaining consistent physical properties even at high filling amounts.
Solution Approach 2:
The patent optimizes particle size distribution parameters (D10: 0.3-1.0 μm, D50: 1.5-3.0 μm, D90: 4.0-6.0 μm) and the volume ratio of fine particles to total particles (10-40%). This parameter control ensures homogeneous dispersion of ferrite powder in the resin composition, maintaining uniform physical properties across the sheet while achieving high filling amounts for improved electromagnetic wave absorbing performance.
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 optimized ferrite powder allows for a highly filled electromagnetic wave absorbing sheet that maintains flexibility and uniform physical properties, while achieving excellent electromagnetic wave absorbing performance in the GHz band.
Implementation Method 1
M-type ferrite has high magnetocrystalline anisotropy. From this, the M-type ferrite exhibits magnetic resonance in the GHz band and indicates an imaginary part u′′ of complex magnetic permeability for obtaining the magnetic loss at that frequency.
Implementation Method 2
the electromagnetic wave energy is lost due to magnetic loss, dielectric loss, or conductive loss
Data Source
AI summary
Provided is a ferrite particle powder for electromagnetic wave absorption that can maintain flexibility and uniformity of physical properties of a sheet even when the sheet is highly filled with the ferrite particle powder and is excellent in electromagnetic wave absorbing performance in a GHz band. The ferrite particle powder is a ferrite particle powder for electromagnetic wave absorption, the ferrite particle powder containing magnetoplumbite-type ferrite represented by a chemical formula of AxFe(12-y)(TizMn(1-z))yO19, where A is at least one selected from Ba, Sr, Ca, and Pb, x is 0.9 to 1.1, y is 5.0 or less, and z is 0.35 to 0.65, and the ferrite particle powder having: a compressed density of 3.00 g/cm3 or more; and an average particle diameter of 0.50 to 3.0 μm determined by an air permeability method (Blaine method).