Samarium magnets

Characteristics of Samarium magnets

• Maximum operating temperature: +350°C
• Highly resistant to oxidation and demagnetisation
• Density 8.2
• Brittle material
• High remanence and coercivity
• High magnetic energy
• Resistant to high temperatures
• Good durability/cost ratio

Samarium-Cobalt magnets are sintered magnets made of an alloy of Samarium and Cobalt. Their maximum magnetic energy ranges from 18 to 30 MGOe.

Samarium magnets were discovered in the 1970s and belong to the so-called rare earth magnets, which refer to 17 metals with exceptional properties. They are used in the manufacture of high-tech products, such as smartphone chips, wind turbines, radar sensors, etc.

Researchers have been interested in these Samarium Cobalt alloys because of their high energy density and superior resistance to demagnetisation. They are very powerful. This material has a maximum energy capacity approximately twice as high as Alnico magnets and six times higher than Ferrites.

The magnets are light grey in colour and have good resistance to corrosion, rust and demagnetisation and therefore do not require surface treatment. However, they should not be exposed to hydrogen and chlorine.

They have a magnetic strength of up to 30 MGOe. Samarium magnets are of very high quality due to their thermal stability and high magnetic strength.

It is a fragile material that needs to be handled with care.

Two main sub-families of Samarium-Cobalt alloys exist: SmCo5 and Sm2Co17. Contrary to SmCo5, Sm2Co17 alloy contains a percentage of iron between 20-25%. Euromag presents you the best performing grade: Sm2Co17.

The working temperatures range from 0 to 350°C. They are the best choice for high temperature applications and for applications where durability is very important, such as in medical devices and the automotive industry

Applications for Samarium-Cobalt magnets are diverse: medical implants and prostheses, temperature pumps, motors, sensors, fixation in ovens, detectors in boilers.

When the magnet is in contact with a soft, flat, clean and sufficiently thick steel frame, the bearing strength is optimal. It decreases for alloyed steels and cast iron (-30% for cast iron). It decreases when there is an air gap, which is the space between the part to be attracted and the pole face of the magnet.

The maximum surface induction value is, at 20°C, of the order of 4000 Gauss for Samarium Cobalt pellets and wafers. This value decreases by 0.04% per degree with increasing temperature. This loss is reversible.