Development of Permanent Magnets for the Reduction of Heavy Rare Earth Elements

ABSTRACT We have investigated the mechanism of coercivity evolution in magnets through multi‐scale microstructural characterization. On the basis of these findings, our goal is to enhance the coercivity of heavy rare‐earth‐lean magnets by optimizing their microstructure. We have developed several new processes and demonstrated improved magnet properties. This review article describes (1) coercivity enhancement by the eutectic alloy diffusion process, (2) the development of light rare earth magnets, and (3) the development of high electrical resistance magnets. Recently, there has been an increasing demand for highly efficient magnet development that not only improves properties but also meets multiple requirements. Accordingly, (4) data‐driven methods are being employed in ongoing magnet development.