Pr-T-B-Ga Anisotropic Magnet Composition for High Coercivity and Remanence
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Solution Overview
Problem
Rare-earth magnets used in motors face a trade-off between coercivity and remanence, where improving one parameter often decreases the other, making it difficult to achieve both high coercivity and remanence simultaneously, especially in high-temperature environments.
Innovation Solution
A Pr-T-B-Ga-based composition with specific atomic percentages and the addition of elements like Nd, Dy, Tb, Cu, and Al, combined with a manufacturing process involving rapid-quenching, cold-pressing, pre-heating, hot-forming, and hot plastic deforming, to align the axes of easy magnetization and enhance magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the remanence is increased to improve the maximum energy product, then the coercivity becomes insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition parameters (Pr: 12.5-15.0 atomic percent, B: 4.5-6.5 atomic percent, Ga: 0.1-0.7 atomic percent) and process parameters (hot plastic deformation conditions, heat treatment parameters) to achieve optimal balance between coercivity and remanence, resolving the trade-off relationship
Solution Approach 2:
The patent uses composite materials by combining Pr-Fe-B base alloy with Ga addition and optional substitutions (Nd for Pr, Dy/Tb for Pr, Cu/Al additions) to create a composite magnetic material system that achieves both high coercivity and high remanence simultaneously
2Reliability
If the coercivity is increased by adding Pr, then the remanence becomes insufficient
Solution Approach 1:
The patent optimizes the Pr content parameter within 12.5-15.0 atomic percent range, which is lower than conventional compositions, to achieve sufficient coercivity while preserving high remanence. The B content (4.5-6.5 atomic percent) and Ga content (0.1-0.7 atomic percent) are also optimized to balance the two properties
Solution Approach 2:
The patent introduces Ga as an intermediary element that modifies the microstructure and magnetic properties, enabling the system to achieve both high coercivity and high remanence. Ga acts as a mediator that facilitates the coexistence of high Pr content for coercivity and appropriate B content for remanence
3Reliability
If the Pr content is increased to improve coercivity, then the difficulty of hot plastic deformation and mold galling increases
Solution Approach 1:
The patent changes the Pr content parameter to a moderate range (12.5-15.0 atomic percent) rather than using high Pr content, which maintains sufficient coercivity while improving hot plastic deformation workability and reducing mold galling. The B content (4.5-6.5 atomic percent) is also optimized to enhance deformation characteristics
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 high coercivity and remanence while maintaining the alignment of magnetic axes, suitable for high-temperature applications without increasing the difficulty of hot plastic deformation or mold galling, and improves the magnetic alignment to 0.92 or more.
Implementation Method 1
hot plastic deforming
Implementation Method 2
align the axes of easy magnetization
Data Source
AI summary
A material for anisotropic magnet, comprising,(1) a Pr-T-B—Ga-based composition containing Pr: 12.5 to 15.0 atomic percent, B: 4.5 to 6.5 atomic percent, Ga: 0.1 to 0.7 atomic percent, and the balance of T and inevitable impurities, wherein T is Fe or obtained by substituting Co for a portion of the Fe; and having,(2) a degree of magnetic alignment of 0.92 or more, wherein the degree of magnetic alignment is defined by remanence (Br)/saturation magnetization (Js); and(3) a crystal grain diameter of 1 μm or less.