Permanent Samarium Cobalt magnets (SmCo) are composed of samarium, cobalt and iron. These rare earth magnets are extremely strong for their small size, metallic in appearance and found in simple shapes such as rings, blocks and discs.
Attributes of Samarium Cobalt
High resistance to demagnetization
High energy (magnetic strength is strong for its size)
Good temperature stability
Expensive material (cobalt is market price sensitive)
Applications of Samarium Cobalt
Computer disc drives, sensors, traveling wave tubes, linear actuators, satellite systems, motors where temporary stability is vital.
For as pressed material, tolerance on the thickness (direction of magnetization) is ± .005. Other dimensions are ± 2.5% or ± .010, whichever is greater.
Magnetizing and Handling
Samarium Cobalt magnets are very brittle and very strong magnetically. Therefore, it is crucial to handle these magnets with extreme care to avoid personal injury and damage to the magnets. Fingers can be severely pinched between attracting magnets. Magnets can chip if allowed to “jump at” an attracting object. It is highly recommended that when constructing rare earth magnetic assemblies, they be magnetized after assembly.
Samarium Cobalt Machining
Since Samarium Cobalt magnet material is prone to chipping and cracking, it does not lend itself to conventional machining methods. It can, however, be abrasively ground, but only with the use of liberal amounts of coolant. The coolant minimizes heat fracturing and the risk of fires caused by oxidized grinding dust.