With remanence similar to neodymium magnets, Samarium cobalt permanent magnets have higher temperature ratings and superior temperature stability, making them arguably the best permanent magnet material commercially available. There are two types of SmCo magnets to choose from: SmCo 1:5 and SmCo 2:17.

The samarium–cobalt 1:5 magnet alloys (generally written as SmCo5 or SmCo 1:5) have one atom of rare earth samarium per five atoms of cobalt. By weight, this magnet alloy typically contains 36% samarium with the balance being cobalt. Sometimes Prasedymium is alloyed to increase the remanence.

The energy products of these samarium–cobalt alloys range from 16 MGOe to 25 MGOe, which is approximately 128 – 200 kJ/m3. Compared to SmCo 2:17 magnets, the 1:5 magnets are relatively easy to magnetize and saturation magnetization can be achieved with a moderate magnetizing field. Therefore, 1:5 magnets are easier to calibrate to a specific magnetic field.

On the other hand, Sm2Co17 magnets (also known as SmCo Series 2:17) are age-hardened with a composition of two atoms of rare-earth samarium per 13–17 atoms of transition metals (TM). The TM content is rich in cobalt but also contains other metals such as iron and copper. Other elements like Zirconium and Hafnium may be added in small quantities to achieve better heat treatment response.

The maximum energy products of these alloys range from 20 to 32 MGOe, which is about 160-260 kJ/m3. These alloys have the best reversible temperature coefficient of remanence of all rare-earth alloys, typically being -0.03%/°C.

The coercivity mechanism in Sm2Co17 magnets is based on domain wall pinning, unlike in SmCo 1:5 and NdFeB magnets where it’s nucleation. The purpose of alloying and heat treatment is to create a microstructure inside the magnets that impedes domain wall motion and thereby resists the magnetization reversal process.

Samarium cobalt rare earth magnets can withstand temperatures up to 350°C without losing their magnetic properties and are the ultimate solution for high-temperature applications that require strong and stable magnetic properties. Their superior temperature stability, combined with their high-energy products and unique composition, make them an excellent choice for a variety of industries, including aerospace, defense, and energy.

If you need a strong, stable, and reliable permanent magnet for your industrial or scientific applications, consider the samarium–cobalt (SmCo) rare earth magnet. With options like SmCo 1:5 and SmCo 2:17 to choose from, you can select the best fit for your specific needs.

1. High magnetic energy density: 

Samarium cobalt permanent magnets have a high magnetic energy density, which means that they can produce a strong magnetic field in a small size.

2. High resistance to demagnetization:

Samarium-cobalt magnets have a high resistance to demagnetization, making them ideal for applications where high stability and reliability are required.

3. High maximum operating temperature:  

SmCo permanent magnets have a high maximum operating temperature, making them suitable for high-temperature applications.

4. Low thermal expansion coefficient:

SmCo rare earth magnets have a low thermal expansion coefficient, which means that their size remains stable even when exposed to temperature changes.

In conclusion, SmCo permanent magnets are an amazing type of rare earth magnet with truly exceptional magnetic properties. They have an extremely high magnetic energy density, an impressive resistance to demagnetization, a high maximum operating temperature, and a low thermal expansion coefficient. These properties make SmCo magnets the perfect choice for a wide range of applications in the motors and generators, aerospace and defense, medical equipment, and sensors industries.