Flake Nanocrystalline Rare Earth Magnets With Fast Hot Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for preparing anisotropic rare earth permanent magnet materials face challenges in enhancing magnetic properties, simplifying the process, and improving production efficiency, as they often result in poor coercivity and complex, inefficient processes.
Innovation Solution
A method involving the preparation of precursor flake nanocrystalline magnetic powder through heat preservation, followed by hot deformation and post-processing to optimize orientation, ensuring flake nanocrystals with specific grain sizes and shape anisotropy are regularly arranged, allowing for high-performance anisotropic magnets to be produced at conventional or rapid deformation rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If repeated hot rolling is conducted to improve orientation degree, then magnetic properties are improved, but residual stress increases and coercivity deteriorates
Solution Approach 1:
The patent applies preliminary action by conducting a first hot rolling process before a second hot rolling process. The first hot rolling creates initial orientation and prepares the microstructure, while the second hot rolling further improves orientation degree. This staged approach allows each rolling pass to be optimized independently, preventing excessive residual stress accumulation that would occur with a single prolonged rolling process, thereby maintaining higher coercivity while achieving good orientation.
Solution Approach 2:
The patent segments the hot rolling process into distinct stages (first hot rolling and second hot rolling) with different parameters and purposes. The first stage focuses on initial orientation and microstructure preparation, while the second stage optimizes the orientation degree. This segmentation allows control over residual stress generation at each stage, preventing the coercivity deterioration that occurs with repeated conventional hot rolling.
2Manufacturing precision
If conventional hot deformation process is used, then anisotropic magnets are produced, but the process is complex and production efficiency is low
Solution Approach 1:
The patent applies parameter changes by optimizing key process parameters including deformation temperature range (400-850°C), deformation amount (30-90%), and deformation rate (0.01-10 mm/s). By establishing specific parameter ranges and relationships, the process achieves consistent anisotropic quality while enabling rapid deformation rates that significantly improve production efficiency compared to conventional methods.
Solution Approach 2:
The patent applies dynamics by enabling rapid deformation rates (0.01-10 mm/s) that are much faster than conventional hot deformation processes. The method dynamically adjusts deformation parameters during processing, allowing the material to achieve proper orientation and anisotropy even at these accelerated rates, thereby dramatically improving production efficiency while maintaining quality.
3Productivity
If rapid deformation rate is applied, then production efficiency is improved, but orientation degree and magnetic properties deteriorate
Solution Approach 1:
The patent applies preliminary action by conducting pre-treatment processes before rapid deformation, including controlling the deformation temperature (400-850°C) to ensure optimal material ductility and orientation response. This preparation allows the material to achieve proper flake orientation even at rapid deformation rates, eliminating the orientation deterioration that normally occurs with high-speed processing.
Solution Approach 2:
The patent applies parameter changes by establishing specific relationships between deformation temperature, deformation amount, and deformation rate. By optimizing these parameters within defined ranges, the process enables rapid deformation (0.01-10 mm/s) while maintaining high orientation degrees and excellent magnetic properties, resolving the contradiction between speed and quality.
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 method achieves anisotropic rare earth permanent magnets with enhanced magnetic properties, including remanence (B r ) of not less than 1.41 T, coercivity (H cj ) of not less than 1050423 A/m, and maximum energy product ((BH) max ) of not less than 363.66689 kJ/m³, while simplifying the process and increasing production efficiency.
Implementation Method 1
preparing a precursor flake nanocrystalline magnetic powder is conducted by subjecting a magnetic powder of a rare earth permanent magnet to heat preservation at a temperature of 710°C to 740°C for 5 min to 120 min under vacuum or a protective atmosphere
Implementation Method 2
orientation treatment by hot deformation: subjecting the precursor flake nanocrystalline magnetic powder or a package or a green body prepared from the precursor flake nanocrystalline magnetic powder to hot deformation at a temperature of 500°C to 850°C, such that the flake nanocrystals are regularly arranged
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A~2B
AI summary
Disclosed are a method for preparing an anisotropic flake nanocrystalline rare earth permanent magnet material and a rare earth permanent magnet material. In the disclosure, the method includes: step 1, preparation of a precursor flake nanocrystal magnetic powder, where a number of grains of flake nanocrystals inside the precursor flake nanocrystalline magnetic powder accounts for not less than 85% of a total number of grains inside the precursor flake nanocrystalline magnetic powder; step 2, orientation treatment by hot deformation: subjecting the precursor flake nanocrystalline magnetic powder or a green body prepared from the precursor flake nanocrystalline magnetic powder to the hot deformation, such that flake nanocrystals are regularly arranged; and step 3, post-processing for optimizing orientation. In the method, the anisotropic flake nanocrystalline rare earth permanent magnet material with excellent magnetic properties is prepared by subjecting the precursor flake nanocrystalline magnetic powder to the hot deformation, easily rotating and orienting the flake nanocrystals during the hot deformation, and post-processing for optimizing orientation. The method has a simple process with easy control and high production efficiency, and is suitable for industrial mass production.