Composite Magnetic Material Rust Prevention via Metallic Soap

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Solution Overview

Problem

Conventional methods for manufacturing electronic components using metal magnetic powders fail to provide effective rust prevention, leading to rust generation during salt water spray tests due to incomplete coating of the metal magnetic powder surfaces with thermosetting resin, and the use of additional coatings like CVD or fluorine coatings is costly and requires avoiding the electrode portion.

Innovation Solution

A composite magnetic material is developed by blending a specific amount of metallic soap with metal magnetic powder and binder resin, where the metallic soap has a melting point lower than the thermosetting temperature, allowing it to melt and coat exposed areas, thereby enhancing rust prevention and embedding an electronic or magnetic element within a composite magnetic molded body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermosetting resin is used to coat metal magnetic powder, then rust prevention is expected, but incomplete coating occurs due to poor wettability, leading to rust generation

Engineering Contradiction:
Improverust prevention performanceVSAvoidcoating completeness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

A silane coupling agent is introduced as an intermediary substance between the metal magnetic powder and the thermosetting resin. The coupling agent contains both inorganic and organic functional groups that form chemical bonds with both surfaces, improving wettability and ensuring complete coating coverage. This mediator resolves the incompatibility between the metal powder surface and the resin, eliminating incomplete coating and rust generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface properties of the metal magnetic powder are modified by treating it with a silane coupling agent, which changes the surface energy and chemical composition. This parameter change in surface characteristics enables better wettability and adhesion of the thermosetting resin, transforming the incomplete coating situation into complete coverage.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If additional coatings (CVD or fluorine coating) are applied to enhance rust prevention, then rust prevention performance is improved, but material cost and machining cost increase

Engineering Contradiction:
Improverust prevention performanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The metal magnetic powder is pre-treated with a silane coupling agent during the mixing process, enabling it to self-coat with the thermosetting resin without requiring additional external coating processes. The coupling agent creates a surface that naturally attracts and bonds with the resin, providing rust prevention functionality through the composite material structure itself, eliminating the need for separate CVD or fluorine coating steps.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The rust prevention function is merged into the composite magnetic material structure by combining the metal magnetic powder, silane coupling agent, and thermosetting resin into a single integrated material system. This eliminates the need for separate protective coatings, reducing both material cost and manufacturing complexity while maintaining effective rust prevention.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If additional coatings are applied to improve rust prevention, then rust prevention is enhanced, but the process becomes more complex and requires avoiding electrode portions

Engineering Contradiction:
Improverust prevention performanceVSAvoidcoating process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The silane coupling agent provides universal compatibility with both the metal magnetic powder and the thermosetting resin, creating a surface treatment that works across the entire component surface without requiring special considerations for different areas. This universal approach eliminates the need to avoid electrode portions, as the coating process applies uniformly to all surfaces including electrode areas.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 composite magnetic material effectively prevents rust on electronic components, maintaining their electric characteristics and mechanical strength, as demonstrated by improved performance in salt water spray tests and strength measurements.

Implementation Method 1

a metallic soap (an organic metallic soap), in which a melting point is equal to or lower than a thermosetting temperature

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the mixed material may be molded and then thermally cured to form a composite magnetic heat-cured body

Methodology Applied
Scientific EffectThermal curing: Phase Change

Data Source

PatentEP3293740B1Composite magnetic material, composite magnetic molded body, electronic component, and method thereof
Publication Date: 2020.08.05 SUMIDA CORP
  • EP3293740B1 patent drawingFigure 1

AI summary

A composite magnetic material includes a metal magnetic powder, a binder resin, and a metallic soap. A melting point of the metallic soap is equal to or lower than a thermosetting temperature of the binder resin. The metallic soap and the binder completely cover an entire surface of the metal magnetic powder. Further, 0.01 wt% < (wt% of the metallic soap) / (wt% of the metallic soap + wt% of the metal magnetic powder + wt% of the binder resin) × 100 < 2.0 wt%.