Samarium Cobalt (SmCo) Magnets

Samarium Cobalt (SmCo) magnets belong to the rare earth family and are made from an alloy of samarium and cobalt. They combine high magnetic performance with exceptional temperature resistance (up to 350 °C) and corrosion resistance. Compared with Neodymium their thermal stability and corrosion resistance are superior, and they are also less brittle. They are ideal for aerospace, energy, automotive and industrial drive applications.

Where temperature is decisive

SmCo picks up where neodymium leaves off. Keeping its magnetic properties up to 350 °C makes it practically the only option in applications around furnaces, inside motors, in aerospace and in sensors operating at high temperature. Its temperature coefficient is also low; in other words, the loss of strength as it heats up fluctuates much less than with neodymium. In measurement and sensor applications this stability is worth more than raw strength.

It needs no coating

Unlike neodymium, SmCo has natural corrosion resistance; it can work uncoated in damp or chemical environments. The absence of a coating is an advantage in close-tolerance assemblies, because coating thickness creates no dimensional uncertainty.

Its cost and limits

Because SmCo contains samarium and cobalt, it is markedly more expensive than neodymium. For this reason it is not chosen unless temperature or corrosion really requires it. Although less brittle than neodymium, it is still a ceramic-like material; it must be protected against impact and bending.

Selection summary