As the third generation of rare earth permanent magnet, ndfeb is 1983 and the high performance permanent magnetic materials.
Nd-fe-b magnetic than cobalt rare earth permanent magnet materials.
Residual magnetic induction intensity at room temperature is up to 1.
47 t, magnetic coercive force of up to 992 ka/m (
12. 4 koe)
9 n/m3 (
50 mg. oe)
, is the magnetic ndfeb permanent magnet material to the highest.
Since the advent of permanent magnet motor in industrial and civil rapid popularization and application.
The deficiency of ndfeb permanent magnet material is low Curie temperature, because it contains a lot of iron and neodymium, easy to rust is also a major weakness of it.
So be on its surface coating processing, now commonly used coating with epoxy resin coating, electrophoresis, electroplating, etc. , general coating thickness for the 10 -
Different coating corrosion resistance, epoxy resin coating solvent resistance, impact resistance, salt fog corrosion resistance good;
Electrophoretic coating solvent resistance, good impact resistance, salt fog resistance is wonderful;
Electroplating has excellent solvent resistance, impact resistance, but poor salt fog resistance.
Therefore need according to the use of magnets environment to choose appropriate protective coating.
In addition, due to the high temperature coefficient of ndfeb permanent magnet materials, can cause its magnetic poor thermal stability.
General ndfeb permanent magnet materials at high temperature, when using the bottom half of the late magnetic curve bending, to use normal ndfeb permanent magnet material, be sure to check the largest permanent magnet demagnetization working point, in order to enhance its reliability.
Tickets for high coercive force ndfeb permanent magnet materials, the coercive force can be greater than 2000 ka/m, some manufacturer has been trial-produced domestic product, its late magnetic curve at 150 ℃ is still linear.