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Development and Applications of Samarium Cobalt Magnets

Posted on May 11, 2017

samarium cobalt supplier

Classified as permanent rare-earth magnets, samarium cobalt magnets have strong magnetic fields and are mainly made of alloy elements of samarium (Lanthanide group) and cobalt. Their development can be dated back to 1966 from the initial research on SmCo5 done by Karl Strnat at Wright-Patterson Air Force and Alden Rey at the University of Dayton. First samarium cobalt magnets generated only had maximum energy products of 18 MGOe (144 kJ/m3) and were advanced to reach 30 MGOe (240 kJ/m3) by 1972. Theoretically, this kind of permanent magnets has a limitation of 34 MGOe (272 kJ/m3) come in either SmCo5 or Sm2Co17.

To make the material selection for your specific application, keep in mind of samarium cobalt magnets’ characteristics. Consider the advantages and disadvantages/limitations when you’re making product designs for your specific applications.

  • Samarium cobalt magnets have a higher Curie temperature than neodymium and are typically used in higher temperature applications.
  • With little amount of iron, they are highly corrosion resistant and often do not require protective plating.
  • They have great resistance to demagnetization from external magnetic fields with Hci up to 25 KOe and their magnetic properties are stable in wider range of temperature variation (kept under their maximum working temperature of 250-350oC). However, if they are exposed to extreme temperature, they may lose partial or entire magnetism. For small sized magnets with lower grades (or Hci values), variance in temperature may have greater impact which may lead to some gain or loss of magnetic fields.
  • Due to physical nature of being hard and brittle, it is challenging or mostly impossible to machine these rare-earth magnets using conventional machining techniques as their dust can be highly combustible. If machining operations are required, they must be performed by diamond tools before magnetization.
  • Industrial samarium cobalt magnets are anisotropic and can only be magnetized in the orientation direction.
With the features mentioned above, let’s take a look at some of the common applications of samarium cobalt magnets.
  • transducers in headphones, microphones, loudspeakers
  • electric guitar pickups
  • electric motors – powered miniature cars
  • medical and dental devices
  • turbo machinery
  • sensor triggering
  • hall effect sensor in fired weapons
  • traveling-wave tube amplifier
  • benchtop NMR spectrometers
  • magnetic pump bearing/couplings
  • material handling equipment
  • humid working environment
  • high temperature environment
  • cryogenic environment (as low as -273 oC)
Being a samarium cobalt magnet supplier over 20 years, we have large selection of sizes in stock for immediate shipping and are able to custom make special design to fit your engineered application.