Neodymium NdFeB (Rare Earth) Magnets

Neodymium NdFeB magnets are, size-for-size, the strongest type of any magnet material that is commercially available (they are stronger than SmCo, Alnico and Ferrite).

Neodymium NdFeB magnets are often the ideal first choice for many applications because they offer a maximum performance from the smallest magnet volume.

Neodymium NdFeB should always be coated to guard against the risk of corrosion – NiCuNi, Zinc, NiCuEpoxy and Gold are popular finishes.

Advantages & Disadvantages of Neodymium Magnets

Advantages 

  • Maximum performance relative to size. Ideal for restricted space or compact applications. 
  • Can be used in extremely cold conditions (e.g. in liquid nitrogen).
  • Standard Neodymium NdFeB is rated to +80 degrees C (176F) maximum. Can be rated to +100 (212F), +120 (248F), +150 (302F), +180 (356F), +200 (392F) and +220/230 degrees C (428/446F) with higher Hci versions.
  • High coercivity (Hci) to resist demagnetisation.
  • NxxT and L-NxxT alloys have better corrosion resistance than standard NdFeB but still needs coating.

Disadvantages

  • Requires a protective coating to prevent the iron in the alloy from corroding (rusting).
  • NxxT and L-NxxT alloys are much more expensive and will still show signs of corrosion.
  • Higher temperature versions contain more Dy element increasing their cost.
  • Nd and Dy prices affect the production cost.
  • Above 150-180 deg C (302-356F), SmCo may be better.

Typical Applications for Neodymium Rare Earth Magnets

  • Motors and Generators
  • Meters
  • Automotive (clamps, sensors)
  • Aerospace
  • Separation (rods, grids, etc) – 10-12kG (22-26lbs) systems
  • High-performance magnetic clamps and pot magnets

Example: An automotive company required a thin disc shaped magnetic clamp to hold two mild steel sections together with maximum force. Even high-grade Neodymium NdFeB disc and ring magnets did not provide enough pull strength performance. Our solution was a dual polarity Neodymium disc magnet within a ring assembly creating a perfect magnetic circuit with a pull force meeting the specification.