Ferrite Powder Composition for Stable High-Frequency Permeability
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Solution Overview
Problem
Conventional ferrite powders experience a decrease in magnetic permeability over time when composited with resin and molded, due to the influence of γ-Fe2O3 with vacant lattice, affecting temporal stability and high-frequency performance.
Innovation Solution
A ferrite powder composition with specific ranges of iron, manganese, and zinc, spheroidal particles, controlled lattice vacancy ratio, and spinel phase to maintain high magnetic permeability and low loss, preventing γ-Fe2O3 generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional ferrite powder is composited with resin and heat-molded, then moldability and filling property are improved, but magnetic permeability gradually decreases over time
Solution Approach 1:
The invention changes the chemical composition parameters of the ferrite powder by strictly controlling the Zn content (0.1-5.0 mass%) and Fe content (balance), and by controlling the lattice vacancy ratio (0-100 mol%). This parameter optimization prevents the formation of γ-Fe2O3 phase while maintaining spheroidal particle morphology, thereby achieving both good moldability and temporal stability of magnetic permeability
Solution Approach 2:
The invention creates a composite ferrite powder system containing spinel phase with controlled lattice vacancies and spheroidal particle morphology. This composite structure combines the benefits of spherical particles (good flowability and filling) with controlled lattice properties (prevention of γ-Fe2O3 formation), resolving the contradiction between manufacturability and long-term magnetic stability
2Productivity
If spherical or polyhedral ferrite particles are used, then fluidity and filling rate are improved, but generation of γ-Fe2O3 with vacant lattice occurs, affecting temporal stability
Solution Approach 1:
The invention optimizes the Zn content parameter (0.1-5.0 mass%) and controls the lattice vacancy ratio (0-100 mol%) to prevent γ-Fe2O3 formation. By adjusting these parameters, the patent maintains spheroidal particle shape for high filling rate while controlling the internal lattice structure to ensure compositional stability and prevent temporal degradation
Data Source
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AI summary
To provide a ferrite powder having excellent temporal stability of a magnetic permeability while maintaining a high filling property, and a high magnetic permeability and a low loss at a high frequency. The ferrite powder contains: 56.0 mass% or more and 63.0 mass% or less of iron (Fe); 7.0 mass% or more and 13.0 mass% or less of manganese (Mn); and 1.0 mass% or more and 3.0 mass% or less of zinc (Zn).