Soft Magnetic Composite Infiltration via Heat-Treated Pore Network

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Solution Overview

Problem

Existing methods for producing soft magnetic composite (SMC) materials face challenges in achieving high mechanical strength and low coercivity, especially at elevated temperatures, while maintaining high density and magnetic properties, due to limitations in current heat treatment and impregnation techniques.

Innovation Solution

A method involving the infiltration of a liquid polymer composite with nanometer-sized and/or micrometer-sized reinforcement structures into a heat-treated compacted body, creating an interpenetrating network that enhances mechanical strength and machinability, allowing for successful impregnation of high-density SMC components with improved properties at elevated temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional heat treatment and impregnation techniques are used to produce SMC materials, then manufacturing process is simple, but mechanical strength and coercivity performance are insufficient especially at elevated temperatures

Engineering Contradiction:
Improvemechanical strengthVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The method applies preliminary heat treatment to the compacted body before impregnation to create an open pore system. This preliminary action prepares the material structure to receive the polymer infiltration, enabling subsequent mechanical strength enhancement without requiring complete process redesign

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention creates a composite material system by infiltrating polymer material into the heat-treated compacted body. The resulting composite combines the magnetic properties of the compacted particles with the mechanical strength and thermal stability of the polymer matrix, achieving high mechanical strength at elevated temperatures

Inventive Principle:
Principle #40Composite materials

2Strength

If high density compacted body is produced to achieve desired magnetic properties, then magnetic permeability and induction are improved, but impregnation difficulty increases and mechanical strength decreases

Engineering Contradiction:
Improvemechanical strengthVSAvoidimpregnation precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

Heat treatment is applied as a preliminary action to the high-density compacted body to create an open pore system. This preliminary treatment opens up the dense structure temporarily, allowing polymer infiltration to occur even in high-density materials that would otherwise be difficult to impregnate

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The method changes the physical parameters of the compacted body through heat treatment, transforming the closed pore structure into an open pore system. This parameter change enables polymer infiltration while maintaining the high density required for good magnetic properties

Inventive Principle:
Principle #35Parameter changes

3Temperature

If organic resin binder is added to improve mechanical strength, then mechanical strength at ambient conditions is good, but heat treatment temperature is restricted below 250°C

Engineering Contradiction:
Improveheat treatment temperatureVSAvoidmechanical strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The invention uses a composite approach where inorganic or thermally stable polymer materials are infiltrated into the compacted body. These materials can withstand high temperatures (above 250°C) while providing mechanical strength, overcoming the temperature limitation of conventional organic resin binders

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The method changes the chemical composition parameters of the binder material from conventional organic resins to thermally stable polymers or inorganic materials. This parameter change enables heat treatment at elevated temperatures while maintaining or enhancing mechanical strength

Inventive Principle:
Principle #35Parameter changes

4Temperature

If inorganic binder is used to withstand higher temperatures, then heat treatment temperature can be increased, but powder properties deteriorate and density levels decrease

Engineering Contradiction:
Improveheat treatment temperatureVSAvoiddensity
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The method separates the functions of binding and heat resistance. Instead of using an inorganic binder throughout the compact, the invention uses heat treatment to create pore structure, then infiltrates polymer material into these pores. This segmentation allows the use of thermally stable materials without compromising the green density and powder properties during compaction

Inventive Principle:
Principle #1Segmentation

5Reliability

If heat treatment is applied to reduce hysteresis losses and increase magnetic permeability, then magnetic properties are improved, but mechanical strength deteriorates

Engineering Contradiction:
Improvemagnetic propertiesVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

Heat treatment is applied as a preliminary action to improve magnetic properties by reducing hysteresis losses and increasing magnetic permeability. After this preliminary treatment, polymer infiltration is performed to restore and enhance mechanical strength, allowing both magnetic and mechanical requirements to be met

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention creates a composite structure where the heat-treated compacted body provides excellent magnetic properties while the infiltrated polymer matrix provides mechanical strength. The composite combines the advantages of both materials, achieving low coercivity and high mechanical strength simultaneously

Inventive Principle:
Principle #40Composite materials

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 method achieves increased mechanical strength, improved machinability, and reduced coercivity in SMC components, enabling high-density and high-strength soft magnetic parts with enhanced performance at elevated temperatures, including noise reduction and acoustic damping properties.

Implementation Method 1

The compacted body is then infiltrated with a liquid polymer composite... enabling the liquid polymer composite to impregnate and/or infiltrate the heat treated compacted body

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

By subsequently solidifying the heat treated compacted body comprising the liquid polymer composite provides an interpenetrating network

Methodology Applied
Scientific EffectPhase change: Phase Change

Data Source

PatentEP2139630B1Powder metal polymer composites
Publication Date: 2013.05.15 HOGANAS AB

AI summary

A method for producing a composite part. The method comprises compacting a powder composition comprising a lubricant into a compacted body; heating the compacted body to a temperature above the vaporisation temperature of the lubricant such that the lubricant is substantially removed from the compacted body; subjecting the obtained heat treated compacted body to a liquid polymer composite comprising nanometer-sized and/or micrometer-sized reinforcement structures; and solidifying the heat treated compacted body comprising liquid polymer composite by drying and/or by at least one curing treatment.