Multiphase Rare-Earth Magnet Structure for High Coercive Force
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Solution Overview
Problem
The increasing demand for Nd—Fe—B magnets is hindered by the scarcity and high cost of neodymium, a rare earth metal, prompting the need for alternative rare earth metals like La and Ce, which compromise magnetic properties when used in place of neodymium.
Innovation Solution
A method for manufacturing a multi-main-phase structure magnet by mixing powders with different rare earth metals (Re1—Fe—B and Re2—Fe—B) and performing anisotropic bulking to create a magnet with improved coercive force and magnetic properties, where the rare earth metals in Re1 and Re2 differ in type or content, and include diffusion regions for enhanced magnetic interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If neodymium (Nd) is used in Nd-Fe-B magnets, then excellent magnetic properties are achieved, but the cost increases and resource scarcity becomes a problem
Solution Approach 1:
The patent creates a multi-phase composite magnet structure combining Re1-Fe-B phase grains and Re2-Fe-B phase grains with different rare earth compositions. This composite approach allows the magnet to achieve excellent magnetic properties through the synergistic interaction of different phases while reducing dependence on pure neodymium, thereby lowering cost and addressing resource scarcity.
Solution Approach 2:
The patent applies local quality by creating distinct phases with different rare earth metal compositions (Re1 and Re2) distributed throughout the magnet structure. Each phase has optimized local composition - Re1-Fe-B provides one set of magnetic properties while Re2-Fe-B provides another, and their combination achieves superior overall performance with reduced neodymium content.
2Ease of manufacture
If lighter rare earth metals like La and Ce are used instead of Nd, then cost decreases and resource availability improves, but magnetic properties deteriorate
Solution Approach 1:
The patent forms a composite structure where Re1-Fe-B phase (containing lighter rare earth metals) and Re2-Fe-B phase (containing different rare earth metals) coexist. The Re2 phase acts as a reinforcing phase that enhances coercive force and magnetic properties, compensating for the weaker magnetic characteristics of lighter rare earth metals in the Re1 phase.
Solution Approach 2:
The patent implements local quality by distributing Re2-Fe-B phase grains throughout the Re1-Fe-B matrix, creating localized regions with enhanced magnetic properties. The Re2 phase provides local reinforcement of coercive force and magnetic interaction, allowing the overall magnet to achieve excellent properties despite using cost-effective lighter rare earth metals in the majority Re1 phase.
3Ease of manufacture
If single-phase structure is used, then manufacturing is simpler, but magnetic properties including coercive force and residual flux density are limited
Solution Approach 1:
The patent employs a multi-phase composite structure with Re1-Fe-B and Re2-Fe-B phases that interact magnetically. The Re2 phase grains dispersed in the Re1 matrix create enhanced magnetic interaction and exchange coupling, significantly improving coercive force and residual flux density beyond what a single-phase structure can achieve, while maintaining manufacturability through a systematic powder mixing and sintering process.
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 produces magnets with superior magnetic properties, including coercive force and residual magnetic flux density, at a lower cost compared to single-phase magnets, while utilizing less expensive and more abundant rare earth metals.
Implementation Method 1
the first phase grains include a first diffusion region formed by diffusion of Re2 in a direction from the outer surface to the center of the first phase grains, and the second phase grains include a second diffusion region formed by diffusion of Re2 in a direction from the outer surface to the center of the second phase grains
Data Source
AI summary
The present disclosure provides a method for manufacturing a multi-main-phase structure magnet having excellent coercive force and a multi-main-phase structure magnet manufactured therefrom.