Magnetic Particle Coating to Prevent Sintering During Heating

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Solution Overview

Problem

Existing methods for manufacturing magnetic particles for magnetic recording struggle to simultaneously reduce particle size and coercive force, as heating processes often lead to sintering and aggregation, hindering further size reduction.

Innovation Solution

A method involving a glass component adhering treatment, where a glass component is partially coated on the magnetic particles before a coercive force-reducing treatment with heating, preventing sintering and allowing for both size reduction and coercive force adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If heating treatment is applied to reduce coercive force, then coercive force is reduced, but particle size increases due to sintering and aggregation

Engineering Contradiction:
Improvecoercive forceVSAvoidparticle size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

A glass component is introduced as an intermediary substance that adheres to the surface of magnetic particles during heating treatment. This glass component acts as a physical barrier that prevents direct contact and sintering between particles while allowing the heating process to proceed, thus reducing coercive force without causing particle aggregation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The glass component is applied to the particle surface before heating treatment to preemptively prevent sintering. By establishing this protective layer in advance, the harmful sintering effect is counteracted before it can occur during the coercive force reduction process.

Inventive Principle:
Principle #9Preliminary anti-action

2Volume of moving object

If glass component is completely coated on magnetic particles to prevent sintering, then sintering is prevented, but coercive force cannot be reduced due to blocking of heating effect

Engineering Contradiction:
Improveparticle sizeVSAvoidcoercive force
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

Instead of uniform complete coating, the glass component is applied in a controlled manner to provide localized protection. The coating density and distribution are optimized to provide sufficient sintering prevention while maintaining adequate heat penetration and magnetic field interaction, allowing both size reduction and coercive force reduction to occur.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Rather than applying a complete thick coating that would block all heating effects, a partial or optimized thickness of glass component is applied. This partial action provides just enough protection against sintering while allowing the necessary thermal and magnetic effects to penetrate and achieve coercive force reduction.

Inventive Principle:
Principle #16Partial or excessive action

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

This approach enables the production of magnetic particles with reduced coercive force and smaller size, improving recording properties while maintaining thermal stability, with coercive force suited for magnetic recording applications.

Implementation Method 1

subjecting starting material magnetic particles to glass component-adhering treatment to be adhered with a glass component

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

subjecting the magnetic particles after the glass component-adhering treatment to coercive force-reducing treatment with heating

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentUS9487411B2Method of manufacturing magnetic particles
Publication Date: 2016.11.08 FUJIFILM CORP

AI summary

The method of manufacturing magnetic particles, wherein the magnetic particles are magnetic particles for magnetic recording, and includes subjecting starting material magnetic particles to glass component-adhering treatment to be adhered with a glass component, and subjecting the magnetic particles after the glass component-adhering treatment to coercive force-reducing treatment with heating, to provide magnetic particles having lower coercive force than the starting material magnetic particles.