Materials Research Institute Successfully Develops Permanent Magnet with 30% Less Neodymium but Same Performance
[Asia Economy Reporter Kim Bong-su] The Korea Institute of Materials Science (KIMS) announced on the 29th that it has succeeded in developing a rare-earth reduced permanent magnet material technology that can reduce the usage of the expensive rare earth element neodymium (Nd) by about 30% while achieving performance comparable to commercial magnets (grade 42M, etc.).
Neodymium (Nd) is very expensive and its supply is highly unstable, but it has been used without alternatives so far because it is essential for realizing the performance of rare-earth permanent magnets. To develop neodymium (Nd)-reduced permanent magnets, the content of neodymium (Nd) must be reduced while increasing the content of the low-cost cerium (Ce). Previous studies could not prevent the deterioration of the magnetic properties of the magnet as the cerium (Ce) content increased.
The research team led by Dr. Lee Jung-gu and Dr. Kim Tae-hoon at the institute focused on clearly identifying the causes and mechanisms of the deterioration of the magnetic properties of magnets due to the increase in cerium (Ce) content and began their research. Based on this, they successfully solved the problem of magnetic property deterioration in rare-earth reduced permanent magnets through atomic-scale microstructure control. They discovered that unnecessary magnetic particles are formed inside rare-earth reduced permanent magnets manufactured by conventional processes and identified these particles as the cause of the deterioration of the magnet’s microstructure and magnetic properties. Accordingly, they conducted research to improve the magnet’s microstructure and enhance its magnetic properties by suppressing the diffusion of atoms constituting the unnecessary magnetic particles to prevent their formation.
The research team applied the melt-spinning method and hot-deformation method, which allow processes with very rapid cooling rates, to the rare-earth reduced precursors and the final permanent magnet manufacturing, respectively, instead of the conventional process. As a result, they succeeded in optimizing the magnet’s microstructure by suppressing the formation of unnecessary magnetic particles inside the magnet. Furthermore, this simultaneously improved the two main characteristics of permanent magnets: remanence and coercivity. Generally, the characteristics of remanence and coercivity in magnets have a trade-off relationship. The team’s technology simultaneously enhances these two key properties, making it highly valuable and efficient from a technical standpoint.
The domestic market size for rare-earth permanent magnets used in high-efficiency motors reached 186 billion KRW annually as of 2021, but almost all of it is imported from overseas. Considering recent issues such as China’s weaponization of rare-earth resources, Japan’s export restrictions on materials, and the global carbon reduction agenda, the localization of rare-earth permanent magnet material technology is an essential challenge to overcome. Once commercialized, it is expected to be utilized in high value-added industrial sectors requiring high-efficiency motors, such as electric vehicles, drones, flying cars, and electric ships.
The research team stated, "Once commercialized, this technology will be a very successful case of technology development that simultaneously solves resource issues and material, parts, and equipment challenges in the domestic rare-earth permanent magnet material sector using purely domestic technology." They added, "This research result is only the beginning, and we will continue to devote ourselves to further research to solidify the role of the Korea Institute of Materials Science and lead the development of South Korea’s rare-earth permanent magnet industry."
The research results were published on the 17th in the academic journal Scripta Materialia.
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