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Neodymium Magnets


Extremely strong for their size, Neodymium (Nd-Fe-B) rare earth magnets are composed of neodymium, iron, boron, and a few transition metals. Not sure if neodymium is the best material for your application? Review our magnetic attribute and application chart

Manufacturing - In general, the elements are melted together and milled into a powder that is dry-pressed to shape in the presence of a magnetic field. The material is then sintered, ground to dimension, magnetized, and tested.

They are called “rare earth” magnets because the elements of neodymium are classified as such in the lanthanides section of the Periodic Table of the Elements.

Tolerances - For as-pressed material, tolerance on the thickness (direction of magnetization) is +/– .005”. Other dimensions are +/– 2.5% or +/– .005”, whichever is greater.

According to International Magnetics Association (IMA) standards, visual imperfections such as hairline cracks, porosity, and minor chips are commonly found in sintered magnets. A chipped edge is considered acceptable if no more than 10% of the surface is missing. Cracks are acceptable as long as they do not extend across more than 50% of the pole’s surface.

Magnetizing and Handling - Neodymium magnets are very brittle and very strong magnetically. Therefore, it is crucial to handle these magnets with extreme care to avoid personal injury and damage to the magnets. Fingers can be severely pinched between attracting magnets. Magnets can chip if allowed to “jump” at an attracting object. It is highly recommended that when constructing rare earth magnetic assemblies, they be magnetized after assembly. These magnets are NOT for children. Please see our safety warnings page for more information. 

Machining - Since Neodymium is prone to chipping and cracking, it does not lend itself to conventional machining methods. It can, however, be abrasively ground before being plated, but only with the use of liberal amounts of coolant. The coolant minimizes heat fracturing and the risk of fires caused by oxidized grinding dust.

View our Neodymium Magnet Collections.

Typical Magnetic and Physical Properties of Neodymium Magnet Material

Neodymium Material Density Max. Energy Product BH (max) Residual Induction Br Coercive Force Hc Intrinsic Coercive Force (Hci) Maximum Operating Temperature Curie Temperature
lbs/in3 g/cm3 MGO Gauss Oersteds Oersteds F C F C
Neodymium 30H 0.267 7.4 30 11000 10500 17000 248 120 626 330
Neodymium 35 0.267 7.4 35 12300 10500 ≥12000 176 80 593.6 312
Neodymium 40 0.267 7.4 40 12900 10500 ≥12000 176 80 593.6 312
Neodymium 42 0.267 7.4 42 13000 9500 ≥11140 176 80 593.6 312
Neodymium 45 0.267 7.4 45 13500 11000 ≥12000 176 80 593.6 312
Neodymium 48 0.267 7.4 48 14200 11600 ≥12000 176 80 593.6 312
Neodymium 52 0.267 7.4 52 14800 10000 ≥11000 140 60 590 310

Since many combinations of elements and orientations are possible, additional grades are available.

Applications of Neodymium Magnets

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

Attributes of Neodymium Material

  • Very high resistance to demagnetization
  • High energy for size
  • Good in ambient temperature
  • Moderately priced
  • Material corrodes easily and should be coated (plated) for long-term maximum energy output
  • Low working temperature for heat applications, but higher levels of heat resistance materials are being introduced periodically

Master Magnetics is your magnet source for neodymium material.  Shop our collection here.