Terbium, a heavy rare earth element (HREE), is malleable and ductile. It is never found in nature as a pure substance but occurs in minerals such as cerite, gadolinite, monazite, xenotime, and euxenite. Nearly all global Terbium mining takes place in China or Myanmar, with refining concentrated in China. While the Nd2Fe14B phase in Neodymium magnets delivers high energy product, remanence, and coercivity, its performance declines significantly at elevated temperatures, making it unsuitable for high-heat applications.
However, substituting a small percentage of Neodymium with Dysprosium or Terbium enhances these high-temperature properties. Terbium outperforms Dysprosium in this role but is costlier due to its lower natural abundance, impacting the Tb price. Terbium is typically used to produce double-high Neodymium magnets (high coercivity and high energy product), where the Tb price plays a key role in cost considerations. To optimize rare earth resource use, stabilize supply chains, and reduce costs, magnet manufacturers and consumers are shifting away from Dysprosium and Terbium. This has led to HREE-less or HREE-free solutions, notably grain boundary diffusion (GBD) technology, as the Tb price continues to influence market trends.
