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Permanent magnets are used in the following major area:
acoustic transducers, motors and generators, magneto mechanical
devices, and magnetic field and imaging systems. You will find
permanent magnets in many products, such as televisions,
telephones, computers, audio systems and
automobiles.
The permanent magnet family
consists, in general terms, of rare earth permanent magnets and
non-rare
earth magnets. Rare earth
magnets include Sm-Co (Samarium-Cobalt) magnets and Nd-Fe-B
(Neodymium-Iron-Boron) magnets. The non-rare earth magnets include
Alnico (Aluminum-Nickel-Cobalt) magnets and Ceramic (Strontium and
Barium Ferrite) magnets.
Although non-rare earth
magnets are used in the majority of these applications due to their
economic cost, rare earth permanent magnets have many
distinguishing characteristics, such as a large Maximum Energy
Product, (one performance
index for permanent magnets). Dozens of magnetic materials which
contain rare earth have been developed recently. Two major families
of rare earth permanent magnets, Sm-Co magnets and Nd-Fe-B magnets,
have been widely used in a variety of applications. Each family has
its own advantages and disadvantages.
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