Bob Johnson Associates - Samarium Cobalt Magnets

Samarium Cobalt Magnets

Known as Rare Earth magnets, Samarium Cobalt (SmCo) are alloys of the Lanthanide group of elements. SmCo magnets have been commercially available since the early 1970’s, first as a 1-5 Type alloy, and later came the introduction of the 2-17 type. Both alloys offer outstanding thermal stability, and excellent corrosion resistance. The 2-17 alloy, offers the advantage of superior thermal stability, and energy products up to 33 MGOe. They are price sensitive, and chip easily.

With the exception of Alnico magnets, SmCo magnets offer the highest operating temperature of any magnetic material. Depending upon the grade, and the permeance coefficient, SmCo magnets can operate at up to 350°C. Additionally, there are specialty grades with 0% Tc/Deg C over selected temperature ranges.

SmCo magnets display extremely high intrinsic coercivity [depending upon the grade]. This not only makes the magnet very difficult to demagnetize, but also requires very high magnetizing fields in order to saturate the magnet.

Because of their high operating temperature, magnetic performance across a broad temperature range, excellent corrosion resistance, and high output per unit mass, SmCo magnets are used in a wide array of applications, including: