| Armstrong Magnetics makes, stocks and magnetizes
permanent magnets, they are: Armstrong
Magnetics ship these permanent magnets magnetized or non-magnetize according to
customers' requests.
Permanent magnets have high coercive force and therefore keep their magnetic
field stably under a proper application after they are magnetized. In
order to evaluate property of permanent magnets, we must take close attention to
the following principal magnetic properties:
Br Residual
induction (or flux density): The higher Br, the
stronger magnetic field the permanent magnet has after magnetizing to
saturation. Neodymium magnets have highest Br
among all types of permanent magnets. Hc
Coercive force and Hci
Intrinsic coercive force: The higher Hc
and Hci, the
stronger resistance of the permanent magnets to demagnetization. Rare earth
magnets have highest Hc
and Hci among
all types of permanent magnets. (BH)max
Maximum Energy Product: It is the maximum energy
that a permanent magnet can supply to an external magnetic circuit when
operating in demagnization. The larger (BH)max,
the more energy a permanent magnet can convert in energy conversion process as a
reversible medium while it is still in stabilized condition. Rare earth magnets
have highest (BH)max among all types of permanent magnets. Tmax
Maximum service temperature: The higher the Tmax,
the higher temperature the permanent magnets
can work stably at. Alnico magnets can work at highest temperature among all
types of permanent magnets. In order to
roughly compare among different types of permanent magnets, take a glance at the
following charts with different colors representing each permanent magnet.
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