Rare Earth Magnets

Rare earth magnets are a vital component found in much of today’s technology and industrial applications, but equally as popular for use with hobbies, crafts, and DIY due to their performance and affordability.

When space is limited and strength is paramount, rare earth magnets are your best option.

What are Rare Earth Magnets?

The term ‘rare earth’ can be misleading as rare earth metals are relatively abundant in the Earth’s crust. However, they are rarely found in large, concentrated deposits, but dispersed among other elements instead. Rare earth magnets are the strongest permanent magnets available and have significantly higher performance than ferrite (ceramic) and alnico magnets.

There are two types of rare earth magnet materials - Neodymium (Nd-Fe-B) and Samarium Cobalt (SmCo).Both materials come in different grades (strengths) and have different magnetic and physical properties.

Neodymium magnets, the stronger of the two, are composed of alloys primarily of neodymium, iron, and boron. These magnets tend to be brittle and are vulnerable to corrosion. Manufacturers typically nickel plate the material to protect it from oxidation.

Attributes of Rare Earth Neodymium

Highest-energy product for its sizeLow mechanical strength - brittle
High coercive forceModerate temperature stability (depending on grade)
Strongest magnet material on the market todayLow corrosion resistance
Very high resistance to demagnetization

Common Applications of Rare Earth Neodymium

  • Magnetic separators
  • Linear actuators
  • Microphone assemblies
  • Servo motors
  • DC motors (automotive starters)
  • Computer rigid disc drives, printers and speakers
  • Medical devices

Samarium Cobalt magnets are made primarily from an alloys of samarium, cobalt, and iron. Typically difficult to demagnetize, samarium cobalt magnets have moderately high operating temperatures and high resistance to corrosion. These magnets can be coated as well.

Attributes of Rare Earth Samarium Cobalt

High corrosion resistanceHigher cost
High-energy productLow mechanical strength - brittle
High temperature stability
High coercive force - resistance to demagnetization

Common Applications of Rare Earth Samarium Cobalt

  • Computer disc drives and sensors
  • Traveling wave tubes
  • Linear actuators and satellite systems
  • Motors where temperature stability is vital

Master Magnetics is dedicated to helping you choose the correct magnet for your application. If you don’t see it here, Contact Us for help.

Customers rely on our team of magnet experts who provide guidance on product design, magnet material and technology, engineering, development, production and more.