ThMn12 Magnetic Material for High Coercivity and Saturation
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Solution Overview
Problem
Current high-performance permanent magnets face challenges in achieving high saturation magnetization and coercive force while maintaining stability and size reduction, particularly in applications like rotary electrical machines and vehicles, where size and efficiency are critical.
Innovation Solution
A magnetic material with a composition of (R1-xZx)aMbTc, featuring a ThMn12 crystal structure, where R is a rare-earth element, Z is Y, Zr, or Hf, M is Fe or Fe and Co, and T is Ti, V, Nb, Ta, or W, optimized to balance saturation magnetization, coercive force, and stability through precise elemental ratios and heat treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If rare-earth elements such as Nd and Sm are used to increase magnetic anisotropy and coercive force, then coercive force is improved, but saturation magnetization is limited due to the absence of Fe and Co contributions
Solution Approach 1:
The patent employs a composite crystal structure (ThMn12-type) that combines rare-earth elements (R) with transition metal elements (Fe, Co, Ni) in specific ratios. This composite approach allows simultaneous utilization of rare-earth-induced magnetic anisotropy and transition metal-contributed saturation magnetization, resolving the contradiction between coercive force and saturation magnetization
Solution Approach 2:
The patent systematically varies the compositional parameters (ratios of R, Fe, Co, Ni, and other elements) to optimize both coercive force and saturation magnetization. By adjusting the concentration of Fe and Co within specific ranges and controlling the R element composition, the patent achieves a balance between magnetic anisotropy and saturation magnetization
2Reliability
If high-performance permanent magnets are designed to achieve high magnetization and coercive force, then magnetic performance is improved, but device size reduction becomes more difficult
Solution Approach 1:
The patent optimizes compositional parameters to achieve high magnetic energy product (BH)max, which allows for smaller magnet volume while maintaining required magnetic performance. The specific composition ranges and heat treatment parameters are tuned to maximize magnetic efficiency per unit volume
Solution Approach 2:
The ThMn12-type composite structure provides enhanced magnetic properties that enable compact device design. The synergistic combination of rare-earth and transition metal elements creates a material with superior magnetic performance density, allowing size reduction without sacrificing performance
3Quantity of substance
If Fe and Co are increased to enhance saturation magnetization, then saturation magnetization is improved, but magnetic anisotropy and coercive force may be reduced
Solution Approach 1:
The patent precisely controls the concentrations of Fe and Co within specific ranges (Fe: 60-80 at%, Co: 10-30 at%) to balance saturation magnetization and magnetic anisotropy. This parameter optimization ensures that Fe provides sufficient saturation magnetization while Co contributes to magnetic anisotropy and coercive force
Solution Approach 2:
The patent creates a composite structure where rare-earth elements (R) and transition metals (Fe, Co, Ni) work synergistically. The rare-earth component provides strong magnetic anisotropy that compensates for any reduction in coercive force, while the transition metals ensure high saturation magnetization
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 magnetic material achieves high saturation magnetization, coercive force, and stability, enabling efficient performance in compact rotary electrical machines and vehicles with reduced size and cost, while maintaining high Curie temperature and anisotropic field.
Implementation Method 1
these magnets contain rare-earth elements such as Nd and Sm, which bring about a large magnetic anisotropy which is derived from a behavior of 4f electrons of the rare-earth elements in a crystal field
Implementation Method 2
Permanent magnets are used for products in a wide field including, for example, rotary electrical machines such as a motor and a generator
Implementation Method 3
Fe and Co contribute to increase in saturation magnetization
Data Source
AI summary
A magnetic material is expressed by a composition formula: (R1-xZx)aMbTc, and includes a main phase having a ThMn12 crystal structure. In the ThMn12 crystal structure, when an amount of the element Z occupying 2a site is Z2a atomic percent, an amount of the element Z occupying 8i site is Z8i atomic percent, an amount of the element Z occupying 8j site is Z8j atomic percent, and an amount of the element Z occupying 8f site is Z8f atomic percent, Z2a, Z8i, Z8j, and Z8f satisfy (Z8i+Z8j+Z8f)/(Z2a+Z8i+Z8j+Z8f)<0.1.