Ferrite Powder Composition for Flexible GHz Absorbing Sheets
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Solution Overview
Problem
Existing electromagnetic wave absorbing sheets using M-type ferrite face challenges in maintaining flexibility and uniformity of physical properties when highly filled, leading to increased viscosity and poor dispersion of components during melt-kneading, which affects processability and physical properties.
Innovation Solution
Optimizing the powder characteristics of M-type ferrite by controlling composition and particle size distribution, with a chemical formula A x Fe (12-y) (Ti z Mn (1-z)) y O 19, to achieve a compression density of 3.00 g/cm 3< or more, D10 of 0.8 µm or less, and D90 of 8.6 µm or less, along with specific surface area and average particle diameter, to enhance dispersibility and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filling amount of ferrite is increased to improve electromagnetic wave absorbing performance, then the electromagnetic wave absorbing performance is improved, but the sheet becomes hard and brittle, making sheet preparation difficult
Solution Approach 1:
The invention changes the particle size distribution parameters of ferrite powder, specifically controlling D10 to 0.8 µm or less and D90 to 8.6 µm or less, with a compression density of 3.00 g/cm³ or more. This parameter optimization allows high filling amounts to be achieved while maintaining sheet flexibility and processability, resolving the contradiction between electromagnetic wave absorbing performance and sheet preparation ease.
2Reliability
If the filling amount of ferrite is increased to improve electromagnetic wave absorbing performance, then the electromagnetic wave absorbing performance is improved, but the resin composition has high viscosity during melting, making fine dispersion difficult
Solution Approach 1:
The invention optimizes the particle size distribution parameters of ferrite powder (D10 ≤ 0.8 µm, D90 ≤ 8.6 µm, compression density ≥ 3.00 g/cm³), which reduces the viscosity of the resin composition during melting. This enables fine dispersion of components even at high ferrite filling amounts, simultaneously achieving high electromagnetic wave absorbing performance and uniform component distribution.
3Quantity of substance
If the resin composition has high viscosity during melt-kneading, then the filling amount of ferrite can be increased, but the additive is not finely dispersed microscopically, deteriorating physical properties
Solution Approach 1:
By optimizing the particle size distribution parameters of ferrite powder (D10 ≤ 0.8 µm, D90 ≤ 8.6 µm, compression density ≥ 3.00 g/cm³), the invention reduces resin composition viscosity during melt-kneading. This enables high ferrite filling amounts while achieving microscopic fine dispersion of additives, maintaining uniform physical properties throughout the sheet.
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 particle powder maintains flexibility and uniformity of physical properties, enabling high electromagnetic wave absorbing performance in the GHz band with improved component dispersion and reduced viscosity during melt-kneading.
Implementation Method 1
Theoretically, the energy is lost due to magnetic loss, dielectric loss, or conductive loss. Magnetoplumbite-type ferrite (hereinafter, sometimes abbreviated as M-type ferrite) has high crystal magnetic anisotropy. From this, the M-type ferrite exhibits magnetic resonance in the GHz band and indicates an imaginary part μ" of complex magnetic permeability, which results in the magnetic loss at that frequency.
Implementation Method 2
Theoretically, the energy is lost due to magnetic loss, dielectric loss, or conductive loss.
Implementation Method 3
Theoretically, the energy is lost due to magnetic loss, dielectric loss, or conductive loss.
Implementation Method 4
Magnetoplumbite-type ferrite (hereinafter, sometimes abbreviated as M-type ferrite) has high crystal magnetic anisotropy. From this, the M-type ferrite exhibits magnetic resonance in the GHz band and indicates an imaginary part μ" of complex magnetic permeability, which results in the magnetic loss at that frequency.
Data Source
Figure 1
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 that is excellent in electromagnetic wave absorbing performance in a GHz band. The ferrite particle powder for electromagnetic wave absorption includes magnetoplumbite-type ferrite represented by a chemical formula: AxFe(12-y)(TizMn(1-z))yO19, in which 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. The ferrite particle powder has a compression density of 3.00 g/cm3 or more, and has a D10 of 0.8 µm or less and a D90 of 8.6 µm or less determined by a laser diffraction method.