Current status and recent topics of rare-earth permanent magnets

TLDR

Rare‑earth Nd–Fe–B magnets are essential for high‑flux applications, with production increasing and shifting toward motor use—especially in hybrid vehicles—while manufacturing relies on powder metallurgy and melt‑spinning/HDDR processes. This paper reviews the current status and future trends in permanent magnet research. The authors survey recent developments and future directions in permanent magnet technology, focusing on manufacturing techniques and applications.

Abstract

After the development of Nd–Fe–B magnets, rare-earth magnets are now essential components in many fields of technology, because of their ability to provide a strong magnetic flux. There are two, well-established techniques for the manufacture of rare earth magnets: powder metallurgy is used to obtain high-performance, anisotropic, fully dense magnet bodies; and the melt-spinning or HDDR (hydrogenation, disproportionation, desorption and recombination) process is widely used to produce magnet powders for bonded magnets. In the industry of sintered Nd–Fe–B magnets, the total amount of production has increased and their dominant application has been changed to motors. In particular, their use for motors in hybrid cars is one of the most attractive applications. Bonded magnets have also been used for small motors, and the studies of nanocomposite and Sm–Fe–N magnets have become widespread. This paper reviews the current status and future trend in the research of permanent magnets.