Fe-Based Nanocrystalline Alloy Composition for Magnetic Components
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Solution Overview
Problem
Fe-based nano-crystalline alloys with high saturation magnetic flux density and magnetic permeability are needed, as existing alloys suffer from low magnetic permeability and poor toughness due to high magnetostriction and rough crystalline particles.
Innovation Solution
An Fe-based nano-crystalline alloy composition with an amorphous phase as the main phase, specifically Fe a B b Si c P x C y Cu z, where 81≤ a ≤ 86 atomic %, 6 ≤ b ≤ 10 atomic %, 2 < c ≤ 8 atomic %, 2 ≤ x ≤ 5 atomic %, 0 ≤ y ≤ 4 atomic %, 0.4 ≤ z ≤ 1.4 atomic %, and 0.08 ≤ z/x ≤ 0.8, is exposed to heat treatment to crystallize bccFe phase, reducing saturation magnetostriction and enhancing magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If nonmetallic elements such as Nb are added to obtain a nano-crystalline alloy, then the alloy structure is improved, but the saturation magnetic flux density is lowered
Solution Approach 1:
The patent removes harmful nonmetallic elements (Nb, Ti, Zr, Hf) from the alloy composition that cause low saturation magnetic flux density, while retaining beneficial elements (B, Si, P, Cu) that enable nano-crystalline structure formation. This selective extraction resolves the contradiction by eliminating the negative impact on magnetic flux density while preserving the nano-crystalline structure through controlled heat treatment.
Solution Approach 2:
The patent optimizes the compositional parameters within specific ranges (Fe: 81-86 at%, B: 6-10 at%, Si: 2-8 at%, P: 2-5 at%, Cu: 0.4-1.4 at%) to achieve both nano-crystalline structure and high saturation magnetic flux density. By precisely controlling these parameters and applying heat treatment at specific temperatures, the patent transforms the alloy properties to simultaneously satisfy both requirements.
2Quantity of substance
If Fe content is increased and nonmetallic elements such as Nb are decreased, then saturation magnetic flux density is increased, but crystalline particles become rough
Solution Approach 1:
The patent applies preliminary heat treatment to the Fe-based alloy before final crystallization. This pre-treatment step prepares the alloy structure by forming an amorphous phase or fine-grained precursor structure, which then serves as a foundation for controlled nano-crystalline formation during subsequent heat treatment. This preliminary action prevents direct formation of rough crystalline particles when high Fe content is used.
Solution Approach 2:
The patent utilizes phase transition mechanisms during heat treatment, transforming the alloy from an amorphous or martensitic phase to a controlled nano-crystalline phase. By controlling the heating rate, holding temperature, and cooling rate, the patent achieves fine-grained crystalline particles with Fe content of 81-86 at%, resolving the issue of particle roughness that would otherwise occur with high Fe content alloys.
3Quantity of substance
If the alloy has high saturation magnetic flux density, then magnetic performance is improved, but magnetostriction increases causing poor toughness
Solution Approach 1:
The patent optimizes the compositional parameters (Fe: 81-86 at%, B: 6-10 at%, Si: 2-8 at%, P: 2-5 at%, Cu: 0.4-1.4 at%) to achieve a balance between saturation magnetic flux density and magnetostriction. By adjusting these parameters within specific ranges and applying controlled heat treatment, the patent reduces magnetostriction to 10×10^-6 or less while maintaining high saturation magnetic flux density of 1.65 T or more, thereby improving both magnetic performance and toughness.
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 resulting alloy achieves high saturation magnetic flux density, high magnetic permeability, and improved toughness with reduced saturation magnetostriction, making it suitable for applications like transformers and motors.
Implementation Method 1
The specific alloy is exposed to a heat treatment so that nanocrystals consisting of bccFe phase can be crystallized
Implementation Method 2
The specific alloy is exposed to a heat treatment so that nanocrystals consisting of bccFe phase can be crystallized
Implementation Method 3
The nanocrystals can remarkably degrease saturation magnetostriction of the Fe-based nano-crystalline alloy
Data Source
Figure 1~3
Figure 4
AI summary
An alloy composition of FeaBbSicPxCyCuz. Parameters meet the following conditions: 79 ≤ a ≤ 86 atomic %; 5 ≤ b ≤ 13 atomic %; 0 < c ≤ 8 atomic %; 1 ≤ x ≤ 8 atomic %; 0 ≤ y ≤ 5 atomic %; 0.4 ≤ z ≤ 1.4 atomic %; and 0.08 ≤ z/x ≤ 0.8. Or, parameters meet the following conditions: 81 ≤ a ≤ 86 atomic %; 6 ≤ b ≤ 10 atomic %; 2 ≤ c ≤ 8 atomic %; 2 ≤ x ≤ 5 atomic %; 0 ≤ y ≤ 4 atomic %; 0.4 ≤ z ≤ 1.4 atomic %; and 0.08 ≤ z/x ≤ 0.8.