What are SmCo-Magnets?

Samarium-Cobalt magnets (SmCo) are a class of permanent magnets made from an alloy of Samarium (Sm) and  Cobalt (Co). These magnets belong to the so-called rare earth magnets, as Samarium is a rare earth element. This group of magnets can be characterized by:

1. Composition: SmCo magnets are made of an alloy of samarium and cobalt. There are two main crystal structures for these magnets:

• SmCo5: This alloy does not contain any additional alloying elements.
• Sm2Co17: This contains iron, copper and zirconium as additional alloying elements.

2. Magnetic properties:

• The maximum magnetic energy density of the alloy SmCo5 is up to 200 kJ/m³.
• The alloy Sm2Co17 even reaches up to 260 kJ/m³.
• By replacing samarium with other rare earths such as praseodymium (Pr) or gadolinium (Gd), the remanence and thus the energy product can be changed.

3. Application temperatures:
 

• The Curie temperature of SmCo magnets is between 700°C and 850°C.
• SmCo5 magnets can be used up to about 250°C.
• Special Sm2Co17 alloys can even be used up to 550°C.

4.  Manufacturing:
  

• SmCo magnets are usually produced by powder metallurgy.
• The metal powder is aligned in a magnetic field and pressed into a green compact.
• Heat treatment gives the magnets their coercive field strength.

5. Application areas:
 

• SmCo magnets are used in rotating electrical machines with permanent excitation, sensors in automotive engineering and chemical pumps.
• Due to their high temperature resistance, they are mainly used at higher application temperatures.
  The improved corrosion resistance and resistance to ionizing radiation are further advantages.
• Although SmCo magnets are brittle, their exceptional magnetic properties make them an important choice in various technical applications.