Samarium cobalt (SmCo) magnets are part of the permanent rare earth family of magnetic materials, alongside the stronger neodymium (NdFeb) magnets. Although samarium cobalt magnets provide approximately two thirds of the strength of neodymium magnets they have significantly greater resistance to corrosion and can withstand much higher temperatures before their performance is affected; making samarium cobalt the magnetic material of choice for particularly demanding applications and harsh environments.
There are two common ranges of grades of samarium cobalt used in modern applications, Sm1Co5 and Sm2Co17. You may also find these grades referred to in shorthand as 1:5 and 2:17, the weaker of the two ranges is 1:5 which includes sub-grades which produce a maximum energy product of 14-24 MGOe (Mega Gauss Oersteds) while the stronger, and more common 1:7 range of grades are capable of producing a maximum energy product between 22 and 32 MGOe.
