Bonded Magnet Ferrite Composition for Magnetic Strength and Elongation
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Solution Overview
Problem
Current ferrite particles and resin compositions for bonded magnets fail to achieve high magnetic force, demagnetization resistance, and mechanical strength, which are essential for advanced applications such as high-performance motors.
Innovation Solution
Ferrite particles with a bulk density of 0.50 to 0.60 g/cm3 and a degree of compaction of 65% or higher, combined with a resin composition containing 83 to 93% ferrite particles and 7 to 17% organic binder, including a silane coupling agent, to produce bonded magnets with enhanced magnetic and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional ferrite particles with high bulk density are used, then magnetic properties are improved, but tensile elongation and mechanical strength deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the bulk density of ferrite particles within the range of 0.35 to 0.55 g/cm³ and the degree of compaction at 65% or more. This optimization of physical parameters enables the resin composition to achieve both high magnetic properties (intrinsic coercivity of 2.0 kOe or more) and excellent tensile elongation (3% or more), resolving the contradiction between magnetic performance and mechanical reliability.
2Force
If ferrite particles with high degree of compaction are used, then magnetic force is enhanced, but dispersibility in resin deteriorates
Solution Approach 1:
The patent resolves this contradiction by optimizing the bulk density parameter to 0.35 to 0.55 g/cm³, which creates an optimal balance between particle compaction and surface characteristics. This parameter range ensures that particles maintain high magnetic force while achieving excellent dispersibility in the resin matrix, as evidenced by the successful production of bonded magnets with intrinsic coercivity of 2.0 kOe or more.
3Strength
If rare earth element magnet particles are used, then magnetic properties are improved, but cost increases
Solution Approach 1:
The patent applies this principle by replacing expensive rare earth element magnet particles with conventional ferrite particles that have been optimized through parameter control. By adjusting the bulk density to 0.35 to 0.55 g/cm³ and degree of compaction to 65% or more, the patent achieves high magnetic properties (intrinsic coercivity of 2.0 kOe or more) using cost-effective ferrite material, thereby reducing production costs while maintaining performance.
4Stability of the object's composition
If ferrite particles with low bulk density are used, then dispersibility is improved, but magnetic properties deteriorate
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal bulk density range of 0.35 to 0.55 g/cm³. This parameter optimization ensures that particles achieve excellent dispersibility in the resin while maintaining sufficient magnetic properties, as demonstrated by the achieved intrinsic coercivity of 2.0 kOe or more in the resulting bonded magnets.
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 exhibit excellent dispersibility and magnetic properties, while the resin composition achieves high tensile elongation, mechanical strength, and improved moldability, making them suitable for applications like rotor components.
Implementation Method 1
including a silane coupling agent
Data Source
AI summary
According to the present invention, there are provided ferrite particles for bonded magnets and a resin composition for bonded magnets which are capable of producing a bonded magnet molded product having a good tensile elongation and exhibiting excellent magnetic properties, as well as a bonded magnet molded product such as a rotor which is obtained by using the resin composition. The present invention relates to ferrite particles for bonded magnets having a bulk density of not less than 0.5 g/cm3 and less than 0.6 g/cm3 and a degree of compaction of not less than 65%, a resin composition for bonded magnets using the ferrite particles, and a molded product obtained by using the ferrite particles and the resin composition.