Soft Magnetic Iron Alloy Plate for High Bs and Low Iron Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing soft magnetic materials for rotating electric machines face challenges in achieving high saturation magnetic flux density (Bs) while minimizing iron loss (Pi), with commercially available materials either having high material costs or compromising on magnetic properties.
Innovation Solution
A soft magnetic iron alloy plate with a chemical composition containing Co by 1 to 30 atom%, N by 0.2 to 10 atom%, and an M component that forms an MN-type nitride, where nitride particles are deposited with an average size of 0.5 μm or less and a number density of 50 particles/100 μm² or less, is developed. This alloy plate is processed using nitrogen immersion heat treatment and sub-zero treatment to generate an Fe—N-based martensite phase while suppressing nitride particle formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electromagnetic pure iron plates are used to achieve high saturation magnetic flux density, then Bs is improved, but iron loss Pi increases due to high coercive force
Solution Approach 1:
The patent changes the chemical composition parameters by adding specific amounts of alloying elements (Si: 1.5-5.0%, Mn: 3.0% or less, Al: 3.0% or less) to pure iron, and changes the microstructural parameters by controlling the ferrite phase content (50% or more) and creating a specific phase mixture (ferrite + martensite or ferrite + bainite). This resolves the contradiction by achieving high Bs through controlled composition while reducing Pi through microstructure optimization that lowers coercive force.
Solution Approach 2:
The patent creates a composite microstructure consisting of multiple phases (ferrite phase combined with martensite phase or bainite phase) within the soft magnetic material. This composite structure allows the material to inherit the high saturation magnetic flux density from ferrite while the dispersed martensite or bainite phases contribute to reduced coercive force and iron loss, effectively resolving the contradiction between high Bs and low Pi.
2Strength
If electromagnetic steel sheets with high mechanical strength are used, then strength is improved, but saturation magnetic flux density decreases compared to pure iron
Solution Approach 1:
The patent applies local quality by creating a non-uniform microstructure where the dominant ferrite phase (50% or more) provides high saturation magnetic flux density in the bulk material, while localized regions contain martensite or bainite phases that provide high mechanical strength. This local differentiation of phases allows the material to simultaneously achieve both high Bs and high strength.
Solution Approach 2:
The patent carefully controls the composition parameters (Si: 1.5-5.0%, Mn: 3.0% or less, Al: 3.0% or less) and microstructural parameters (ferrite phase content: 50% or more) to balance magnetic and mechanical properties. By adjusting these parameters, the material achieves a optimal combination where the ferrite matrix ensures high Bs while the controlled additions of alloying elements and secondary phases provide the required mechanical strength.
3Strength
If alloying elements are added to improve mechanical strength and magnetic properties, then strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise parameter ranges for alloying elements (Si: 1.5-5.0%, Mn: 3.0% or less, Al: 3.0% or less) that can be achieved using conventional steelmaking processes. These parameter ranges are designed to be compatible with existing manufacturing capabilities, allowing the complex multi-phase microstructure to be produced through standard rolling and heat treatment processes without requiring exotic manufacturing techniques.
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 soft magnetic iron alloy plate achieves a saturation magnetic flux density higher than that of electromagnetic pure iron plates while keeping iron loss at 60 W/kg or less, thereby enhancing the performance and reducing the cost of rotating electric machines.
Implementation Method 1
an M component that can form an MN-type nitride by 0.5 atom % or more and 5 atom % or less, wherein when a cross section of the soft magnetic iron alloy plate is observed, nitride particles of the M component are deposited with an average particle size of 0.5 μm or less
Implementation Method 2
A soft magnetic iron alloy plate with a chemical composition containing Co by 1 to 30 atom%, N by 0.2 to 10 atom%, and an M component that forms an MN-type nitride
Implementation Method 3
processed using nitrogen immersion heat treatment and sub-zero treatment to generate an Fe—N-based martensite phase
Data Source
AI summary
Provided are a soft magnetic iron alloy plate that can suppress an excessive increase in Pi while exhibiting Bs higher than that of an electromagnetic pure iron plate and reduce the cost as compared with permendur, an iron core using the soft magnetic iron alloy plate, and a rotating electric machine. The soft magnetic iron alloy plate according to the present invention includes a chemical composition containing Co by 1 to 30 atom %, N by 0.2 to 10 atom %, an M component that can form an MN-type nitride by 0.5 to 5 atom %, with the balance being Fe and impurities, and when a cross section of the soft magnetic iron alloy plate is observed, nitride particles of the M component are deposited with an average particle size of 0.5 μm or less and a number density of 50 particles/100 μm2 or less.