Make a debut into the rare-earth permanent magnet market dominated by China and Japan!

A research team led by Dr. Jung-Goo Lee and Dr. Tae-Hoon Kim of the Department of Magnetic Materials in the Powder Materials Division at the Korea Institute of Materials Science(KIMS), a government-funded research institute under the Ministry of Science and ICT, succeeded in developing rare-earth-saving permanent magnets that can replace the 42M-graded commercial magnets while reducing the amount of neodymium (Nd), an expensive rare-earth, by about 30%. The technology has a significant value as it achieved the commercial magnet-level of performance, which is currently used in the industry, even though the amount of high-priced rare-earth resource is reduced.

Neodymium (Nd) is expensive and unstably supplied, but it has been inevitably used, as it is essential for manufacturing rare earth permanent magnets. In order to develop a neodymium (Nd) reduced permanent magnet, the content of cerium (Ce), an inexpensive element, has to be increased, instead of reducing the content of neodymium (Nd). Until now, with the increased content of cerium (Ce), it was not able to prevent the deterioration of the magnetic properties. The research team focused on clarifying the reason and mechanism of the deterioration of the magnetic properties caused by the increased cerium (Ce) content, and they successfully solve the problem of rare-earth-reduced permanent magnets by controlling atomic-scale microstructure

The researchers discovered that unnecessary magnetic particles were formed during manufacturing process, which are the underlying reason for the deterioration of the magnetic and microstructural properties of the magnets. They modified the microstructure and enhanced the magnetic properties by preventing the diffusion of atoms so that the formation of unnecessary magnetic particles is suppress

The research team applied the melt-spinning method and the hot-deformation method, which have very fast cooling rate compared to the conventional process, to the process in fabricating rare-earth-reduced precursors and final bulk magnets, respectively. As a result, they succeeded in optimizing the microstructure of the magnets by suppressing the formation of unnecessary magnetic particles. In addition, they were able to simultaneously improve the residual magnetization and coercive force, which are the main properties of permanent magnets. As the residual magnetization and coercive force are in a trade-off relationship, the technology that improves both main properties is very useful and valuable.

The domestic market of the rare-earth permanent magnets for high-efficiency motors is worth 186 billion won per year in 2021, but Korea depends on imports of the material. Considering the current issues such as the context of China's weaponization of rare-earth resources, Japan's export restrictions on magnetic materials, and global carbon neutrality, localization of rare-earth permanent magnet materials is necessary for Korea. When this technology is commercialized, it can be used in high value-added industries such as electric vehicles, drones, flying cars, and electric ships that require high-efficiency motors.

Dr. Tae-Hoon Kim, a senior researcher at KIMS, who led the research team, said, “When the technology is commercialized, it will simultaneously solve the resource problems and material, parts, and equipment issues in the domestic rare-earth permanent magnet markets. This is only the beginning. With further research in the future, we will spare no effort to lead the development of the domestic rare earth permanent magnet industry.”

This research was supported by the fundamental research program of the KIMS,‘Development of magnetic composite materials with tunable magnetic performance’, funded by the Ministry of Science and ICT. In addition, on March 17th, the research results were published in Scripta Materialia, one of the world's top 5 academic journals in the field of metal materials (The first author, Gayoung Kim, Ph.D. student, Title: High-performance Ce-substituted) (Nd0.7Ce0.3)-Fe-B hot-deformed magnets fabricated from amorphous melt-spun powders).

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About Korea Institute of Materials Science(KIMS)

KIMS is a non-profit government-funded research institute under the Ministry of Science and ICT of the Republic of Korea. As the only institute specializing in comprehensive materials technologies in Korea, KIMS has contributed to Korean industry by carrying out a wide range of activities related to materials science including R&D, inspection, testing&evaluation, and technology support.