Compression bonded magnet material is made of the powerful magnetic material mixed into an epoxy binder. The mix is approximately 97 vol% magnet material to 3 vol% epoxy; much of the magnetic strength of the permanent magnetic material is retained. Since the material is formed by compression bonding, the dimensions vary +/-.002″ or better for a given run.
Bonded permanent magnetic material is isotropic , so it can be magnetized through any direction, including multi-polar arrangements. Because the material is in an epoxy binder, it can be machined on a mill or lathe. Bonded permanent magnetic material is often used to substantially reduce the size of design that used ceramic magnet materials. Significant size reductions can be achieved because bonded NdFeB material is approximately 3 times stronger than ceramic magnet material. In addition, since bonded permanent magnetic material is isotropic, it can be magnetized multi-polar, such as a multi N-S-N-S pattern on the outer diameter of a ring. Bonded NdFeB magnets are more prone to oxidation than any other magnet alloys. If bonded NdFeB magnet is to be exposed to humidity, chemically aggressive media such as acids, alkaline solutions, salts and harmful gases, coating is recommended. It is not recommended in a hydrogen atmosphere.