Textured Electrical Steel Sheet via Particle Alignment

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Solution Overview

Problem

Existing methods for producing electrical steel sheets face challenges in achieving mechanically stable and magnetically anisotropic structures due to the agglomeration of uniaxially magnetized iron particles during additive manufacturing, which impede layer formation and alignment, and the brittleness of soft magnetic sintered metals limits directed flux guidance.

Innovation Solution

A method involving the application of a paste containing iron oxides or hydroxides on a carrier plate, aligning particles in a predetermined magnetic flux direction, followed by solvent removal and reduction in a reductive atmosphere to create a textured iron structure with anisotropic properties through sintering, while using additives to enhance mechanical strength and anisotropy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If uniaxially magnetized iron particles are used in additive manufacturing, then magnetic anisotropy is improved, but particle agglomeration occurs which impedes layer formation and alignment

Engineering Contradiction:
Improveparticle alignmentVSAvoidlayer formation
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent changes the magnetic state parameter of iron particles from ferromagnetic to superparamagnetic, which eliminates strong magnetic moment and prevents agglomeration while maintaining alignment capability during the printing process

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a binder as an intermediary material that facilitates layer formation and provides mechanical stability during printing, allowing particles to be deposited in controlled layers without direct particle-to-particle contact that would cause agglomeration

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If soft magnetic sintered metals are used, then complex shapes can be produced, but mechanical stability is insufficient due to brittleness

Engineering Contradiction:
Improveshape complexityVSAvoidmechanical stability
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent creates a composite structure by combining superparamagnetic iron particles with a binder material, forming a mechanically stable composite that overcomes the brittleness of sintered metals while maintaining shape complexity capabilities

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the magnetic properties parameter by using superparamagnetic particles instead of ferromagnetic particles, which eliminates magnetic domain wall movements that cause magnetostriction and mechanical stress, thereby improving mechanical stability

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If iron particles are aligned during deposition, then magnetic anisotropy is improved, but mechanical stability deteriorates due to lack of fixation

Engineering Contradiction:
Improveflux guidanceVSAvoidmechanical stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The binder acts as an intermediary that fixes the aligned iron particles in their oriented positions, providing mechanical stability while preserving the magnetic anisotropy achieved during alignment

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs particle alignment during the deposition process before the binder fully sets, ensuring that particles are oriented in the desired magnetic flux direction and then fixed in place by the binder

Inventive Principle:
Principle #10Preliminary 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 method enables the production of a textured metal sheet with magnetically anisotropic properties, improving mechanical stability and flux guidance, and is cost-efficient by integrating texturing in the alloy's preliminary stage, maintaining anisotropic microstructure and shape anisotropy.

Implementation Method 1

removing the solvent by heating

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 2

reducing the particles to iron by removing the oxygen of the iron oxide or the hydroxyl group of the iron hydroxide in a reductive atmosphere

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 3

providing the electrical steel sheet by sintering the aligned particles

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 4

aligning the particles in direction of a predetermined magnetic flux direction

Methodology Applied
Scientific EffectMagnetic field alignment: Magnetic Field

Data Source

PatentEP3715018B1Texturing of electrical sheets
Publication Date: 2022.07.20 SIEMENS AG
  • EP3715018B1 patent drawingFigure 1~2

AI summary

The invention discloses a method for producing an electrical steel sheet (4) comprising the steps of: a) applying (S1) a paste to the surface of a substrate, wherein the paste contains antiferromagnetic, ferrimagnetic and/or weakly ferromagnetic particles and a solvent, b) aligning (S2) the particles in the direction of a predetermined magnetic flux direction, c) removing the solvent (S3) by heating, d) providing (S5) the electrical steel sheet (4) by sintering the aligned particles, and e) separating (S6) the electrical steel sheet (4) from the substrate. The invention also discloses an electrical steel sheet (4) and an electrical machine (1).