Rare earth elements and permanent magnets (invited)

TLDR

Rare earth magnets, essential to industries from aerospace to medicine, deliver high induction and coercivity through 3d‑4f interactions, and for over 40 years have been the top choice for high‑field, high‑temperature applications, though >95 % of rare‑earth oxides are sourced from China. The paper discusses the magnetic properties and applications of rare‑earth magnets, reviews the past, present, and future of the permanent‑magnet industry, and offers insights into new technologies and design choices that could alleviate supply‑chain concerns. EEC specializes in producing RECo5 and RE2TM17 sintered magnets, using samarium and gadolinium as key ingredients in powder‑metallurgical processes such as melting, crushing, jet milling, pressing, sintering, and heat treating.

Abstract

Rare earth (RE) magnets have become virtually indispensable in a wide variety of industries such as aerospace, automotive, electronics, medical, and military. RE elements are essential ingredients in these high performance magnets based on intermetallic compounds RECo5, RE2TM17 (TM: transition metal), and RE2TM14B. Rare earth magnets are known for their superior magnetic properties—high induction, and coercive force. These properties arise due to the extremely high magnetocrystalline anisotropy made possible by unique 3d-4f interactions between transition metals and rare earths. For more than 40 years, these magnets remain the number one choice in applications that require high magnetic fields in extreme operating conditions—high demagnetization forces and high temperature. EEC produces and specializes in RECo5 and RE2TM17 type sintered magnets. Samarium and gadolinium are key RE ingredients in the powder metallurgical magnet production processes which include melting, crushing, jet milling, pressing, sintering, and heat treating. The magnetic properties and applications of these magnets will be discussed. We will also briefly discuss the past, current, and future of the permanent magnet business. Currently, over 95% of all pure rare earth oxides are sourced from China, which currently controls the market. We will provide insights regarding current and potential new magnet technologies and designer choices, which may mitigate rare earth supply chain issues now and into the future.