Ferrite Particles for Electromagnetic Wave Shielding
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Solution Overview
Problem
Existing electromagnetic wave shielding materials using ferrite particles are ineffective in shielding electromagnetic waves across a wide frequency band, particularly failing to provide adequate shielding in the 550 MHz to 1 GHz range.
Innovation Solution
Ferrite particles with a single crystalline body structure, spherical shape, and specific composition (3-25 wt% Mn, 43-65 wt% Fe, and optional 0-3.5 wt% Mg and 0-1.5 wt% Sr) are used in a resin composition, achieving high magnetic permeability and effective electromagnetic wave shielding across 1 MHz to 1 GHz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ferrite particles with larger particle size are used, then magnetic permeability is improved, but dispersion uniformity in resin composition deteriorates
Solution Approach 1:
The patent optimizes the particle size parameter to 10 μm or less, which balances magnetic permeability requirements with dispersion uniformity in resin compositions. This size parameter ensures sufficient magnetic properties while preventing aggregation and achieving homogeneous distribution in the shielding material.
2Reliability
If ferrite particles with irregular shape are used, then magnetic permeability is improved, but manufacturing precision and particle uniformity deteriorate
Solution Approach 1:
The patent specifies that ferrite particles should have a spherical shape with roundness of 0.96 or more. This geometric parameter optimization maintains magnetic permeability while ensuring uniform particle morphology, which improves manufacturing precision and consistency in the final shielding material product.
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 ferrite particles provide high magnetic permeability and effective electromagnetic wave shielding across the 1 MHz to 1 GHz frequency band, ensuring uniform shielding performance and preventing particle aggregation in the resin composition.
Implementation Method 1
a real part μ′ of a complex magnetic permeability measured using a molding composed of the ferrite particles and a binder resin has a maximal value in a frequency band of 100 MHz to 1 GHz
Data Source
AI summary
An object of the present invention is to provide ferrite particles having a high magnetic permeability in a frequency band of 1 MHz to 1 GHz. Another object is to provide a resin composition containing the ferrite particles and an electromagnetic wave shielding material composed of the resin composition. The ferrite particles are composed of a single crystalline body having an average particle size of 1 to 2000 nm and has a spherical particle shape, wherein the ferrite particles contain substantially no Zn, 3 to 25 wt % of Mn, and 43 to 65 wt % of Fe, and a real part μ′ of a complex magnetic permeability measured using a molding composed of the ferrite particles and a binder resin has a maximal value in a frequency band of 100 MHz to 1 GHz.