Introduction
Samarium (atomic number 62) is a Light Rare Earth Element, though sometimes grouped with mediums based on processing. It was the first rare earth to be used to create commercially viable permanent magnets, predating the Neodymium magnet revolution.
Chemical & Physical Properties
A silvery metal, relatively stable in air at room temperature compared to lighter lanthanides, but it ignites at high temperatures (around 150°C).
Occurrence & Production
Found in standard REE minerals like monazite and bastnäsite. It is generally more abundant than the heavier rare earths needed for high-performance magnets.
Key Applications & Uses
- Samarium-Cobalt (SmCo) Magnets: Before NdFeB magnets, SmCo magnets were the strongest available. While weaker than NdFeB, SmCo magnets have a major advantage: they retain their magnetic strength at much higher temperatures and are highly resistant to corrosion. This makes them preferred for high-performance aerospace applications, military hardware, and specific industrial pumps.
- Nuclear Control Rods: Samarium-149 is a strong neutron absorber, making it useful in nuclear reactor control rods to regulate the fission process.
- Catalysts: Used in organic chemistry for specific synthetic reactions.
Future Outlook & Significance
While Neodymium dominates the mass magnet market, Samarium remains vital for critical applications where high heat and corrosive environments would destroy a standard Neodymium magnet.