Compression bonded magnets are the magnets of maximum strength but
comparatively with less physical strength. The tooling costs are
relatively low as compared to injection mold. For making compressed
magnets neodymium-iron-boron (NdFeB) grades as well as crushed and
powdered samarium cobalt (SmCo) are used. As ferrites are ultra small
they are not used. For improving adhesion in the magnetic powder, to
enhance their corrosion resistance, epoxy binder is used. Due to
epoxies, bonded magnets are capable of being used at or above 180°C. Properties
Following are the properties of compression magnets:
The
higher magnetic density provides the compressed magnets with higher
magnetic strength.
- They are resistant to automotive fluids and industrial solvents.
- The epoxy coat prevents oxidation.
- They have good mechanical strength.
- They can be easily machined.
- Since the materials are isotropic, they can be magnetized in any
direction.
- The tools are available in rings, discs and rectangles.
The compression bonded magnets are used in various fields like
- DC motors
- Sensors
- Rotors
- Printers