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What is Samarium Cobalt Magnet?

July 05,2023

Samarium-cobalt magnets were introduced in the 1970s and were the first commercially available rare earth magnets. Their introduction was revolutionary, three times the maximum energy product of any other magnet at the time. Before the introduction of samarium-cobalt magnets, the standard for magnetic materials was an aluminum alloy magnet. Samarium-cobalt magnets were the strongest until their increasing production costs prompted engineers to look for cheaper alternatives and formulate Ndfeb magnets, which are now the strongest magnets in the world.

The most commonly used grade of samarium-cobalt magnets is made of about 35% (Sm) and 60% (Co) and a small amount of iron (Fe), copper (Cu), (Hf) alloy (Z) and praseodymium (Pr). Some grades of samarium cobalt magnets are made entirely of samarium and cobalt and have excellent corrosion resistance.

Temperature of SmCo magnets:

Samarium cobalt magnets are called SmCo magnets, which belong to the rare earth permanent magnet system column like Ndfeb magnets. Although they are not as powerful as neodymium magnets, they have two distinct advantages over neodymium magnets.

They are in a higher temperature range and are more resistant to corrosion. And from 150 degrees Celsius will be better than the high temperature resistance of the Ndfeb magnet.

Usually, the maximum working temperature of ordinary Ndfeb magnets is only 80 degrees Celsius. Therefore, in relatively high temperature environments or applications, samarium cobalt magnets are also a good choice.

Samarium-cobalt magnets not only perform well at high temperatures, but also retain their magnetic properties even at temperatures below absolute dew (-273 degrees Celsius), making them popular in low-temperature applications.

Samarium-cobalt magnets are resistant to corrosion:

Since most grades of samarium cobalt magnets contain little or no iron, this gives them excellent corrosion resistance, while neodymium magnets typically contain 60-75% iron. Therefore, samarium cobalt magnets generally do not require electroplating treatment.

Samarium-cobalt magnet magnetic properties:

Compared with the NdFeb magnet, the magnetic properties are not as good as the samarium cobalt magnet, but the magnetic properties are stronger than the general magnetic ferrite, which is equivalent to a low grade NdFeb magnet.

The Price of Samarium-Cobalt magnet:

Due to the cost of producing samarium, samarium cobalt magnets have the disadvantage of being expensive compared to neodymium magnets. Like other rare earth magnets, they are also very brittle and therefore best suited for applications that do not require direct impact.

Use of Samarium-cobalt magnets:

Because of their properties, samarium-cobalt magnets are most commonly used in applications that require high temperature work, such as generators, pump couplings, sensors, motors, Marine applications, and automotive, aerospace, military, food, and manufacturing industries.