ThMn12 Magnetic Material Suppressing Alpha Phase Precipitation
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Solution Overview
Problem
Current magnetic materials face challenges in achieving high saturation magnetization while maintaining high coercive force and anisotropic magnetic field, particularly in high-temperature regions, due to the precipitation of unwanted phases that reduce magnetic performance.
Innovation Solution
A magnetic material composition with a ThMn12 type crystal phase as the main phase, optimized by controlling the concentrations of rare-earth elements, Fe, Co, and other elements to suppress the precipitation of α-(Fe, Co) and Nd3(Fe, Ti) phases, thereby enhancing saturation magnetization and coercive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the concentration of Fe and Co is increased to achieve high saturation magnetization, then saturation magnetization is improved, but unwanted phases such as α-(Fe, Co) precipitate which reduces coercive force
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentrations of Fe, Co, and rare-earth elements within specific ranges. By adjusting these compositional parameters, the patent achieves high saturation magnetization while suppressing the formation of unwanted α-(Fe, Co) phases that would reduce coercive force. The specific concentration ranges are optimized to balance magnetic properties.
Solution Approach 2:
The patent creates a composite magnetic material system combining rare-earth elements (Nd, Sm, Pr, Dy) with Fe, Co, and other elements (Al, Si, Mn, Cu, Ni, Ga, In, Zn, B). This composite approach allows the material to achieve both high saturation magnetization from Fe-Co and high coercive force from rare-earth elements, while the synergistic interaction suppresses unwanted phase precipitation.
2Reliability
If rare-earth elements are added to increase coercive force through magnetic anisotropy, then coercive force is improved, but saturation magnetization decreases due to dilution of Fe-Co content
Solution Approach 1:
The patent optimizes the concentration parameters of rare-earth elements (Nd: 5-20 at%, Sm: 5-20 at%, Pr: 0-10 at%, Dy: 0-10 at%) to achieve the right balance. By controlling these parameters within specific ranges, the patent ensures sufficient rare-earth content for high coercive force while maintaining adequate Fe-Co content for high saturation magnetization.
Solution Approach 2:
The patent applies local quality by creating a heterogeneous microstructure where rare-earth rich regions provide magnetic anisotropy and coercive force, while Fe-Co rich regions provide saturation magnetization. This spatial distribution of different elemental concentrations allows both properties to coexist at the macro level.
3Strength
If high Fe-Co content is used to achieve high saturation magnetization, then saturation magnetization exceeds 1.48 T, but α-(Fe, Co) phase precipitation occurs which reduces magnetic performance
Solution Approach 1:
The patent introduces rare-earth elements (particularly Nd and Sm) as intermediary elements that mediate between Fe and Co atoms. These rare-earth elements act as spacers that prevent excessive Fe-Co clustering and α-(Fe, Co) phase precipitation, while still allowing sufficient Fe-Co content to maintain high saturation magnetization.
Solution Approach 2:
The patent extracts or removes the harmful α-(Fe, Co) phase formation tendency by introducing rare-earth elements that preferentially bind with Fe and Co atoms, preventing them from forming the unwanted α-(Fe, Co) phase. This selective extraction of the harmful interaction mechanism preserves the beneficial high magnetization properties.
4Strength
If the material composition is optimized for high saturation magnetization, then saturation magnetization is improved, but anisotropic magnetic field decreases in high-temperature regions
Solution Approach 1:
The patent optimizes compositional parameters including adding Dy (0-10 at%) and Tb (0-5 at%) which have high magnetic anisotropy and high Curie temperatures. These elements enhance the thermal stability of the anisotropic magnetic field while maintaining high saturation magnetization through the balanced Fe-Co content.
Solution Approach 2:
The patent creates a multi-element composite system that combines elements with different thermal properties. The Fe-Co base provides high saturation magnetization, while rare-earth elements (Nd, Sm, Dy, Tb) provide thermal stability and maintain anisotropic magnetic field at elevated temperatures, creating a synergistic composite material.
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 solution achieves higher saturation magnetization and coercive force, with saturation magnetization exceeding 1.48 T and anisotropic magnetic field above 3 MA/m, while maintaining stability and reducing unwanted phase precipitation.
Implementation Method 1
Fe and Co contribute to increase in saturation magnetization
Implementation Method 2
rare-earth elements such as Nd and Sm, which brings about a large magnetic anisotropy which is derived from a behavior of 4f electrons of the rare-earth elements in a crystal field
Implementation Method 3
large magnetic anisotropy which is derived from a behavior of 4f electrons of the rare-earth elements in a crystal field
Implementation Method 4
behavior of 4f electrons of the rare-earth elements in a crystal field
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
An magnetic material is a magnetic material expressed by a composition formula: (R1-xYx)aMbTcAd, which includes a main phase consisting of a ThMn12 type crystal phase. 30 atomic percent or more of the element M in the composition formula is Fe.