Nitride-Phase Soft Magnetic Powder for Lower Core Loss

Solution Overview

Problem

Existing soft magnetic powders experience a significant increase in coercivity and core loss when subjected to pressure molding, which is detrimental to the performance of electronic components.

Innovation Solution

Incorporating nitride phases with specific area and ratio within the soft magnetic alloy particles, which help relieve stress and suppress eddy currents, thereby reducing the increase in coercivity and core loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If pressure molding is applied to soft magnetic powder, then the powder can be molded into a predetermined shape, but the coercivity increases significantly

Engineering Contradiction:

Improvemolded shapeVSAvoidcoercivity

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

Nitride phases are introduced into the soft magnetic alloy particles before pressure molding to preemptively relieve stress during the molding process. This preliminary inclusion of stress-relieving phases prevents the coercivity increase that would otherwise occur during pressing, allowing the powder to be molded into predetermined shapes while maintaining low coercivity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention creates a composite structure by incorporating nitride phases (such as Si3N4, Si2N2O, or SiO2) within the soft magnetic alloy particles. This composite material approach combines the magnetic properties of the soft magnetic alloy with the stress-relieving properties of the nitride phases, enabling both shape molding and low coercivity to be achieved simultaneously.

Inventive Principle:

Principle #40Composite materials

2Shape

If pressure molding is applied to soft magnetic powder, then the powder can be molded into a predetermined shape, but the core loss increases

Engineering Contradiction:

Improvemolded shapeVSAvoidcore loss

Core Design Contradiction:

ShapeVSLoss of energy

Solution Approach 1:

Nitride phases are introduced into the soft magnetic alloy particles before pressure molding to preemptively relieve stress during the molding process. This preliminary inclusion of stress-relieving phases prevents the coercivity increase that would otherwise occur during pressing, allowing the powder to be molded into predetermined shapes while maintaining low coercivity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention creates a composite structure by incorporating nitride phases (such as Si3N4, Si2N2O, or SiO2) within the soft magnetic alloy particles. This composite material approach combines the magnetic properties of the soft magnetic alloy with the stress-relieving properties of the nitride phases, enabling both shape molding and low coercivity to be achieved simultaneously.

Inventive Principle:

Principle #40Composite materials

3Power

If the saturation magnetic flux density is increased, then the power efficiency is improved, but the coercivity increases

Engineering Contradiction:

Improvepower efficiencyVSAvoidcoercivity

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The invention creates a composite structure by incorporating nitride phases (such as Si3N4, Si2N2O, or SiO2) within the soft magnetic alloy particles. This composite material approach combines the magnetic properties of the soft magnetic alloy with the stress-relieving properties of the nitride phases, enabling both shape molding and low coercivity to be achieved simultaneously.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the internal structure parameters of the soft magnetic alloy particles by controlling the size and distribution of nitride phases. By maintaining specific particle size ranges (0.5-50 μm) and controlling nitride phase content (1-30 at%), the material achieves both high saturation magnetic flux density and low coercivity, resolving the trade-off between power efficiency and reliability.

Inventive Principle:

Principle #35Parameter changes

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 presence of nitride phases in the soft magnetic alloy particles effectively lowers the coercivity increase and core loss, enhancing the performance and efficiency of electronic components.

Implementation Method 1

For the soft magnetic powder including the soft magnetic alloy particle containing a nitride phase, stress caused by pressure molding is relieved due to the presence of the nitride phase, and it is thought that the increase of the coercivity can be prevented.

Methodology Applied

Scientific EffectStress relaxation: Stress Relaxation

Implementation Method 2

Also, due to the presence of the nitride phase, eddy current is suppressed, and core loss which includes eddy current loss can be lowered. It is thought that the reason for this is because the powder resistance has improved due to the presence of the nitride phase.

Methodology Applied

Scientific EffectEddy current suppression: Eddy Currents

Data Source

PatentUS20250333823A1Soft magnetic alloy particle, soft magnetic powder, dust core, and electronic component

Publication Date: 2025.10.30 TDK CORP

AI summary

A soft magnetic alloy particle including Fe and Si. One to twenty nitride phases are observed in a cross-section of the soft magnetic alloy particle, an area per each of the nitride phases is within a range of 0.0005 to 10 μm2, and an area ratio of the observed nitride phases occupying the cross-section of the soft magnetic alloy particle is within a range of 0.1 to 2%.