Aligned Iron Nitride Magnets for Nanoparticle Anisotropy Control
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Solution Overview
Problem
Existing rare-earth-free permanent magnetic materials face challenges in aligning nanoparticles due to electrostatic and electromagnetic forces, leading to agglomeration and reduced magnetic properties, such as low energy product and remnant magnetization.
Innovation Solution
The development of aligned iron nitride nanoparticles with α″-Fe16N2 phase domains, which exhibit a specific ratio of integrated x-ray diffraction peak intensities and squareness measurements, overcoming the tendency to form agglomerates and enhancing magnetic properties through controlled processing and alignment techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nanoparticles are consolidated to form permanent magnets, then magnetic properties are improved, but electrostatic and electromagnetic forces cause nanoparticles to form agglomerates that hinder alignment
Solution Approach 1:
The patent uses a binder material as an intermediary substance to consolidate nanoparticles into permanent magnets while preventing harmful agglomeration. The binder acts as a mediating matrix that holds nanoparticles in place without allowing electrostatic and electromagnetic forces to cause excessive clustering, thereby maintaining both magnetic properties and nanoparticle dispersion stability.
2Manufacturing precision
If external force is applied to align nanoparticles, then magnetic anisotropy is improved, but agglomerates prevent individual nanoparticles from rotating in response to alignment force
Solution Approach 1:
The patent applies segmentation by breaking down the agglomerate structure into individual nanoparticles through controlled consolidation processes. This segmentation allows external alignment forces to act on individual particles rather than on large agglomerates, enabling precise nanoparticle alignment while reducing the complexity of agglomerate formations.
3Reliability
If rare earth elements are used for permanent magnets, then magnetic performance is improved, but supply constraints and high prices limit availability
Solution Approach 1:
The patent applies parameter changes by transitioning from rare earth element compositions to iron nitride-based compositions. This fundamental material parameter change maintains magnetic performance through optimized iron nitride nanoparticle properties (size, shape, crystalline structure) while eliminating dependence on scarce rare earth elements, thereby resolving the contradiction between magnetic performance and material availability.
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 aligned iron nitride nanoparticles result in anisotropic nanocomposite magnets with improved squareness and energy product, leading to higher remnant magnetization and coercivity, suitable for advanced magnetic applications.
Implementation Method 1
If the nanoparticles have sufficiently large magnetic anisotropy, an external force may be used to align the nanoparticles prior to and/or during consolidation
Implementation Method 2
a ratio of integrated intensities of an α′′-Fe16N2 (004) x-ray diffraction peak to an α′′-Fe16N2 (202) x-ray diffraction peak
Implementation Method 3
an external force may be used to align the nanoparticles prior to and/or during consolidation
Data Source
AI summary
Disclosed herein is a permanent magnet comprising: a plurality of aligned iron nitride nanoparticles wherein the iron nitride nanoparticles include α″-Fe16N2 phase domains; wherein a ratio of integrated intensities of an α″-Fe16N2 (004) x-ray diffraction peak to an α″-α″-Fe16N2 (202) x-ray diffraction peak for the aligned iron nitride nanoparticles is greater than at least 7%, wherein the diffraction vector is parallel to alignment direction, and wherein the iron nitride nanoparticles exhibit a squareness measured parallel to the alignment direction that is greater than a squareness measured perpendicular to the alignment direction.