NdFeB magnets (Neodymium-Iron-Boron) |
- Rare Earth Permanent Magnets
| Rare earth permanent magnet NdFeB (Neodymium-Iron-Boron) is a new kind of magnetic material developed in the
1980's with excellent magnetic characteristics (high energy product and high coercive force etc.)
and relatively low cost. It is getting to replace the traditional magnets of hard ferrite, AlNiCo
and SmCo in many fields such as electro-accoustic devices, electric motors, sensors/transducers, instruments and
meters, auto industry, petro-chemical industry and magnetic health-care products etc.
NdFeB magnets are very powerful. They have a higher Maximum Energy Product, (BH)max, than SmCo magnets. (BH)max
of NdFeB can easily reach 30 MGOe and even goes up to 52 MGOe. NdFeB magnets can replace SmCo magnets in most
cases, especially where operating temperature is less than 80°C.
The temperature stability of NdFeB is not as good as SmCo magnets. Magnetic performance of NdFeB magnets
will deteriorate rapidly above 200°C. Compared to SmCo magnets, the corrosion and oxidation resistance of NdFeB
is relatively low. Therefore, A surface coating is usually applied on NdFeB magnets. Zinc or nickel coating is
common used as a protective layer. Other materials such as gold, brass, tin or polymer (epoxy) are also used
for this purpose.
NdFeB magnets can be made either in Sintered or Polymer-bonded Magnets.
Industrial magnets like NdFeB are used when a lot of sticking power are needed, yet for limited space.
NdFeB can come in disks, blocks and rings etc.