The Nano Materials Research Division at the Korea Institute of Materials Science (KIMS), under the leadership of Dr. Tae-Hoon Kim and Dr. Jung-Goo Lee, has made a groundbreaking advancement in the development of high-performance permanent magnets, eliminating the need for costly and scarce heavy rare earth elements. This marks the world’s first successful implementation of this innovative approach.
Permanent magnets are essential components in high-tech applications such as electric vehicle (EV) motors, robotics, and advanced home appliances. Traditionally, the production of these magnets has relied heavily on rare earth elements, particularly the heavy ones, which are mainly produced in China. This reliance has led to high resource dependence and inflated production costs, creating a need for alternative solutions.
In response to these challenges, the research team at KIMS developed a new method for producing high-end permanent magnets without the use of expensive heavy rare earths. At the core of this breakthrough is a two-step grain boundary diffusion process (GBDP), which improves the magnets’ magnetic properties without relying on heavy rare earths.
The grain boundary diffusion process is designed to enhance the coercivity, or the magnet’s ability to retain its magnetization. Traditionally, this involves coating heavy rare-earth materials onto the surface of the magnet and subjecting it to a high-temperature heat treatment. The rare-earth materials then diffuse into the magnet’s interior along the grain boundaries, boosting its magnetic performance.
KIMS’s innovation involves a novel twist on this process. The team developed a two-step procedure that begins by thermally infiltrating a high-melting-point metal-containing material into the magnet at elevated temperatures. This is followed by cooling the material at room temperature. In the second step, a low-cost light rare earth material, such as Praseodymium (Pr), is reintroduced into the magnet at high temperatures.
A major challenge in traditional grain boundary diffusion processes is the phenomenon of abnormal grain coarsening, which can degrade diffusion efficiency and weaken the magnet’s performance. The KIMS team successfully addressed this issue, enabling faster diffusion and better overall performance. As a result, the magnets achieved coercivity levels equivalent to those made with heavy rare earths, with performance grades ranging from 45SH to 40UH.
The breakthrough technology not only reduces costs but also offers a solution to the heavy reliance on rare earths, which have become increasingly scarce and expensive. If commercialized, this advancement could revolutionize industries that rely on high-efficiency motors, such as the electric vehicle, drone, and flying car sectors.
Dr. Tae-Hoon Kim, the principal investigator, emphasized the significance of the discovery: “The use of expensive heavy rare earth elements in magnets for high-performance applications like electric vehicle motors has been a significant challenge. While researchers have been exploring alternatives for years, progress has remained limited. With this novel approach, we believe we can break free from the dependence on heavy rare earths in magnet manufacturing.”
This breakthrough could place South Korea at the forefront of permanent magnet technology, offering a competitive edge in industries where high-performance magnets are essential. Furthermore, it opens up new research avenues for grain boundary diffusion processes, which could play a central role in future magnet technologies.
By Impact Lab
