SmCo magnets (Samarium Cobalt) are also part of the rare earth family. The compound of Samarium Cobalt was discovered
in 1966 by Dr. Karl J. Strnat. They were once the most powerful permanent magnet, but NdFeB magnets have surpassed them.
Samarium cobalt is a powdered metal which is compacted when it is near a magnetic field and then sintered. Sintered means
that when a compacted powder magnet is exposed to heat treat operation, the full density and magnetic orientation can be
attained.
SmCo magnets have also a very strong magnetic field. They tend to resist
demagnetization extremely well. Unlike Neodymium magnets, it is also very corrosion resistant.
SmCo magnets can operate at higher temperatures up to 300°C and are widely used in applications
in which higher operating temperature and higher corrosion and oxidation resistance are crucial.
The temperature coefficient of remanence is usually less than ±0.05%.
Two common compositions of SmCo magnets are SmCo5 and Sm
2Co17. They can be sintered and
bonded. Generally, the cost of SmCo magnets is higher than NdFeB magnets. But NdFeB magnets are
stronger than SmCo magnets.
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