Samarium Cobalt – The Other Rare Earth Magnet

By Shalea Hardison

When you think of rare earth magnets, most us think of neodymium magnets. But samarium cobalt magnets also are classified as rare earth magnets.

Rare earth magnets are permanent, high-strength magnets made from alloys of rare elements. Rare earth elements come from the Lanthanoid series of elements on the periodic table. In the case of neodymium magnets, neodymium is the rare earth element. Samarium provides the rare earth element in samarium cobalt magnets.

First, there was Samarium Cobalt

Before neodymium became synonymous with the term rare earth magnet, samarium cobalt magnets made its first debut as a rare earth magnet. Samarium cobalt was first patented by the U.S. Materials Laboratory in 1966, and a second patent followed in 1972, from Raytheon.

At the time, samarium cobalt magnets offered three times the strength of commercially available alnico magnets. However, researchers continued to look for stronger and lower-cost magnets and neodymium magnets became the strongest magnet and joined samarium cobalt as the other rare earth magnet.

Features and Characteristics

Like their neodymium counterparts, samarium cobalt magnets possess extreme strength in a small size (although slightly less than neodymium). That is the hallmark of rare earth magnet. However, samarium cobalt magnets have other characteristics, including:

• Reliable Performance – SmCo magnets are extremely resistant to demagnetization making them a reliable performer in many environments
• Corrosion Resistant – Thanks to having little iron in their composite, SmCo magnets have excellent corrosion resistance
• Temperature Stable – SmCo maintain their magnetic properties both at high temperatures (480-572 degrees F) and extremely low temperatures (-450 degrees F)
• Brittle Material – As SmCo magnets are sintered, the material can be brittle. These magnets can chip easily if allowed to ‘jump’ at an attracting magnet or object. It’s ideal to use these magnets in applications where direct, repeated contact won’t occur

Practical Uses for Samarium Cobalt Magnets

Because of these unique characteristics, samarium cobalt magnets most often are used in applications where high operating temperatures favor these magnets. Find samarium cobalt magnets in these applications:

Generators Pump couplings Motors of all kinds Computer disc drives Sensors Traveling wave tubes Linear actuators Satellite systems

Wondering if samarium cobalt is the best rare earth magnet for your use? Our Magnet Experts are happy to help you choose the right magnet for your application.