Soft Magnetic Composite Powder Coating That Resists Press Cracking

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Solution Overview

Problem

Existing methods for producing iron-based soft magnetic composite powders face issues with insulating coatings breaking during compression molding, leading to increased production costs and safety burdens due to the use of organic solvents and impurities like aluminum orthophosphate affecting coating strength.

Innovation Solution

A method involving the use of aluminum dihydrogen tripolyphosphate dihydrate and silicone resin coatings on iron-based soft magnetic particles, with specific intensity ratios and temperature controls to form robust insulating layers without organic solvents, ensuring high adhesion and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If condensed phosphate metal compound (e.g., aluminum tripolyphosphate) is added to harden the insulating coating, then the adhesion strength between the soft magnetic powder and the insulation layer increases, but the insulating coating may break during compression molding due to the high hardness of added substances like Al2O3 and SiO2

Engineering Contradiction:
Improveadhesion strengthVSAvoidintegrity of insulating coating
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the insulating coating by specifying precise ratios of Al2O3 (0.1-5 wt%) and SiO2 (0.1-5 wt%) within the condensed phosphate metal compound. This parameter optimization ensures the coating has sufficient adhesion strength while maintaining flexibility and preventing breakage during compression molding.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite insulating coating formed by condensed phosphate metal compound that contains both Al2O3 and SiO2 in controlled amounts. This composite structure combines the adhesion benefits of aluminum compounds with the flexibility and crack-resistance benefits of silicon compounds, resolving the contradiction between strength and integrity.

Inventive Principle:
Principle #40Composite materials

2Temperature

If basic substances like Al2O3 and SiO2 are added as hardening accelerators to the condensed phosphate metal compound, then the hardening effect is enhanced, but the insulating coating becomes more prone to breaking during compression molding

Engineering Contradiction:
Improvehardening effectVSAvoidflexibility of insulating coating
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The invention optimizes the concentration parameters of hardening accelerators by limiting Al2O3 to 0.1-5 wt% and SiO2 to 0.1-5 wt% of the total condensed phosphate metal compound. This controlled parameter adjustment provides sufficient hardening effect while preventing excessive brittleness that would cause coating breakage during compression molding.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If impurities like aluminum orthophosphate are present in condensed phosphoric acid metal salts, then the availability and cost-effectiveness are improved, but the strength of the insulating coating is negatively affected

Engineering Contradiction:
Improveavailability of raw materialsVSAvoidstrength of insulating coating
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention establishes precise compositional parameters for the condensed phosphate metal compound, specifying Al2O3 at 0.1-5 wt% and SiO2 at 0.1-5 wt%. This parameter control allows the use of commercially available condensed phosphoric acid metal salts that may contain impurities like aluminum orthophosphate, while ensuring the final coating meets strength requirements through controlled composition.

Inventive Principle:
Principle #35Parameter changes

4Strength

If organic solvents are used when adding silane coupling agent to strengthen adhesion, then the adhesion between inorganic insulating powder and soft magnetic powder is improved, but production costs increase due to solvent drying treatment and safety control burdens

Engineering Contradiction:
Improveadhesion strengthVSAvoidproduction process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the organic solvent step from the production process. Instead of using silane coupling agents requiring organic solvents and subsequent drying, the invention directly uses condensed phosphate metal compounds that form insulating coatings through simple mixing and heating, removing the complex solvent handling and drying equipment requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive and complex organic solvent-based adhesion processes with a simpler, more economical approach using condensed phosphate metal compounds. This substitution eliminates the need for costly solvent recovery systems and safety infrastructure while achieving comparable or superior adhesion strength.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 method produces an iron-based soft magnetic composite powder with insulating coatings that are less likely to break during compression molding, maintaining high efficiency and reducing production costs by avoiding solvent use and impurity effects.

Implementation Method 1

stirring and mixing the aluminum dihydrogen tripolyphosphate dihydrate powder and the iron-based soft magnetic powder while heating the powders to a maximum arrival temperature of 130° C. or higher and 200° C. or lower

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

for the spectrum when the aluminum dihydrogen tripolyphosphate dihydrate powder is analyzed by X-ray diffraction method, the peak intensity of the (112) plane of aluminum dihydrogen tripolyphosphate dihydrate is 1.5 times higher than the peak intensity of the (102) plane of aluminum orthophosphate

Methodology Applied
Scientific EffectCrystallisation: Crystallisation

Implementation Method 3

adding a silicone resin powder to the first composite powder and stirring and mixing the silicone resin powder and the first composite powder, wherein the temperature of the powders during the stirring and mixing is 80° C. or higher

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentUS20260027617A1Method for producing iron-based soft magnetic composite powder and iron-based soft magnetic composite powder
Publication Date: 2026.01.29 JFE STEEL CORP

AI summary

It is provided a method for producing an iron-based soft magnetic composite powder and the iron-based soft magnetic composite powder. The method for producing an iron-based soft magnetic composite powder includes a first mixing step of adding an aluminum dihydrogen tripolyphosphate dihydrate powder to an iron-based soft magnetic powder and stirring and mixing the aluminum dihydrogen tripolyphosphate dihydrate powder and the iron-based soft magnetic powder to obtain a first composite powder in which coating layers of aluminum dihydrogen tripolyphosphate dihydrate are formed on the surfaces of iron-based soft magnetic particles, wherein, for the spectrum when the aluminum dihydrogen tripolyphosphate dihydrate powder is analyzed by the X-ray diffraction method, the peak intensity of the (112) plane of aluminum dihydrogen tripolyphosphate dihydrate is 1.5 times higher than the peak intensity of the (102) plane of aluminum orthophosphate.