Fe16N2 Permanent Magnet Microstructure Without Rare Earths
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Solution Overview
Problem
Current permanent magnets rely heavily on rare earth elements, which are scarce and expensive, leading to supply shortages and environmental concerns due to mining, and their production involves high energy consumption and costs.
Innovation Solution
Development of bulk permanent magnets composed of Fe16N2 with high saturation magnetization and magnetic anisotropy, utilizing a polycrystalline microstructure with elongated grains and controlled grain boundaries, formed through processes involving annealing, nitriding, and magnetic field annealing to enhance magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rare earth elements are used in permanent magnets, then high energy product and magnetic performance are achieved, but supply shortage, high cost, and environmental deterioration occur
Solution Approach 1:
The patent extracts and eliminates rare earth elements from the permanent magnet composition while maintaining magnetic performance through Fe16N2-based formulations. The invention specifically removes dependency on neodymium and other rare earth elements by using iron-nitride compounds as the primary magnetic phase, thereby resolving the contradiction between achieving high energy product and ensuring material availability.
Solution Approach 2:
The patent substitutes expensive rare earth elements with abundant, inexpensive iron and nitrogen materials. The Fe16N2-based permanent magnets use readily available iron as the base material, dramatically reducing material cost while maintaining competitive magnetic energy product, thus resolving the cost-availability contradiction.
2Reliability
If rare earth elements are used in permanent magnets, then high magnetic performance is achieved, but production cost increases
Solution Approach 1:
The patent replaces expensive rare earth elements with inexpensive iron and nitrogen materials. The Fe16N2-based formulation uses abundant iron as the primary component, eliminating the need for costly neodymium, dysprosium, or other rare earth metals, thereby dramatically reducing production cost while maintaining high magnetic energy product.
Solution Approach 2:
The patent changes the compositional parameters from rare earth-based alloys to iron-nitride compounds with specific stoichiometry (Fe16N2). This parameter change in material composition, combined with controlled microstructure development through processing, achieves high magnetic performance using low-cost materials.
3Manufacturing precision
If conventional sintering process is used for permanent magnets, then dense microstructure is achieved, but high energy consumption and manufacturing complexity occur
Solution Approach 1:
The patent utilizes phase transition mechanisms during processing to achieve dense microstructure without conventional high-temperature sintering. The Fe16N2 formation and microstructure development occur through controlled phase transformations during cooling and heat treatment, reducing the need for energy-intensive sintering processes while maintaining microstructural density.
4Quantity of substance
If rare earth elements are mined for permanent magnet production, then magnetic material supply is ensured, but severe environmental deterioration occurs
Solution Approach 1:
The patent extracts and eliminates the need for rare earth element mining by using Fe16N2-based materials. This removes the harmful environmental impacts associated with rare earth mining operations, including habitat destruction, water pollution, and radioactive waste, while ensuring continuous supply of magnetic materials through abundant iron resources.
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 Fe16N2 magnets offer a high magnetic energy product comparable to rare earth magnets without rare earth elements, reducing environmental impact and production costs, and enhancing efficiency in applications like motors and generators.
Implementation Method 1
Fe16N2 has high saturation magnetization and magnetic anisotropy constant
Implementation Method 2
Bulk Fe16N2 permanent magnets may provide an alternative to permanent magnets that include a rare earth element because Fe16N2 has high saturation magnetization and magnetic anisotropy constant
Implementation Method 3
carrying out a microstructure build-up by annealing the prepared raw material at an elevated temperature
Implementation Method 4
subsequently quenching the prepared raw material to produce a microstructure build-up material
Implementation Method 5
nitriding the reduced material to produce a nitrided material
Implementation Method 6
magnetic field annealing the nitrided material
Data Source
AI summary
The disclosure is directed to an iron-nitride material having a polycrystalline microstructure including a plurality of elongated crystallographic grains with grain boundaries, the iron-nitride material including at least one of an α″-Fe16N2 phase and a body-center-tetragonal (bct) phase comprising Fe and N. The disclosure is also directed a method producing an iron-nitride material. The method includes some combinations of preparing a raw material comprising iron, carrying out a microstructure build-up by annealing the prepared raw material at an elevated temperature and subsequently quenching the prepared raw material to produce a microstructure build-up material, annealing the microstructure build-up material, reducing the microstructure build-up material in a hydrogen environment, nitriding the reduced material to produce a nitrided material and subsequently quenching the nitrided material to a martensitic transformation temperature, stress annealing the nitrided material, and magnetic field annealing the stress-annealed material.