Ferrite are composed of barrium/strontium carbonate and iron oxide. They are charcoal gray in color and usually appear in the forms of discs, rings, blocks, cylinders, and sometimes arcs for motors.
Attributes of Ferrite Magnets -
High intrinsic coercive force
Tooling is expensive
Least expensive material compared to alnico and rare earth magnets
Limited to simple shapes due to the manufacturing process
Lower service temperature than alnico, greater than rare earth
Finishing requires diamond cutting or grinding wheel
Lower energy product than alnico and rare earth magnet
Applications of Ferrite Blocks -
DC brushless motors, Magnetic Resonance Imaging (MRI), Magnetos used on lawnmowers and outboard motors, DC permanent magnet motors (used in cars), Separators (separate ferrous material from non-ferrous), Used in magnetic assemblies designed for lifting, holding, retrieving, and separating.
Applications of Ferrite Rings -
Ring magnets are made specifically for loudspeaker systems and their sizes have evolved with demand from this market. However, they are also commonly used in magnetic rollers for separating applications and in the printing industry. They are also a vital component found in fast running conveyor systems in many manufacturing plants dealing with ferrous material.
Applications of Ferrite Arc -
Arc magnets are a unique shape which are designed especially for motors, generators and alternators and are commonly used for both rotors and stators. They are also used in magnetic flywheel assemblies. In motor design a ring of magnets with alternating polarities on the inner radius rotate in close proximity to a number of copper coils. As the copper passes through the magnetic fields an electric current is induced within the copper.
Four or more magnets with an equal number of north and south polarity on the inner radius can be used to create a multi-pole ring. All arc magnets are available with either pole on the inner radius.