Highlights
- SmCo magnets are experiencing a strategic resurgence in defense applications due to their exceptional thermal stability and unique performance capabilities.
- Despite accounting for less than 2% of global permanent magnet usage, SmCo magnets are irreplaceable in critical military systems like radar, sonar, and missile guidance.
- Western defense sectors face critical challenges in securing samarium and cobalt supplies.
- China controls rare earth element exports and processing technologies.
Samarium, once eclipsed in the rare earth magnet market, is surging back into strategic relevance. According to Professor Koen Binnemans, Head of the SOLVOMET Group at KU Leuven, the resurgence of samarium-cobalt (SmCo) magnets reflects the cyclical and often misunderstood dynamics of the global rare earths (REE) supply chain.
SmCo magnets were once dominant in the 1970s–80s until their high cost and limited field strength ceded the market to neodymium-iron-boron (NdFeB) alternatives. But what SmCo lacks in affordability, it makes up for in military-grade performance. With Curie temperatures between 700–800°C, and operational stability up to 550°C, these magnets are uniquely suited for extreme defense environments—including radar arrays, sonar systems, missile guidance, magnetic actuators, and the F-35 Joint Strike Fighter.
Today, SmCo magnets account for less than 2% of global permanent magnet usage. Yet, as China tightens its grip on REE exports—including Sm, Co, and processing tech—the West’s strategic dependence becomes harder to ignore. “SmCo magnets may be expensive and brittle, but they are irreplaceable in the defense sector,” writes Binnemans.
Key insights from Binnemans’ post and research:
- Historical bottlenecks: Sm supply once capped SmCo magnet production.
- Technical specs: SmCo5 and Sm₂Co₁₇ offer high thermal and demagnetization resistance.
- Export risks: China’s restrictions threaten secure access for Western militaries.
- Cobalt volatility: Price instability in cobalt further complicates supplyplanning.
Rare Earth Exchanges (REEx) notes that strategic stockpiles and secure offtake agreements for samarium must now be prioritized alongside neodymium and dysprosium. Despite its current market oversupply, Sm’s military demand is poised to rise fast—and Western defense industrial bases are unprepared.
REEx recommends immediate U.S. DPA-backed action to support SmCo magnet R&D, secure processing outside China, and finance vertically integrated magnet manufacturing for critical systems. The defense of tomorrow will not run on batteries alone—it will rely on high-heat magnets that don’t crack under fire.
Source: Koen Binnemans, KU Leuven/SOLVOMET Group
Further reading: Rare Earths and the Balance Problem, Journal of Sustainable Metallurgy (2018)
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