Plastic Magnets and Currents
Are plastic magnets electrically conductive?
It just depends on how much plastic there is, and on the magnetic powder in it. If there is a
minimum amount of plastic gluing the iron particles together, they might touch each other often
enough to let electricity get across a whole chunk of plastic
magnet. But there are many reasons the electricity might be stopped instead, such as iron-
oxide instead of iron, or surface-oxidation on the iron particles, or more plastic between
them. I suspect you will usually find them insulating, but it's best not
to rely on them to block high voltage. Their breakdown voltage will be much lower than
plastics with no metal powder in them.
A true plastic magnet is not conductive. It is polarized. Every atom has its own little
magnetic field, in both conductors and nonconductors. In any permanent magnet, many of the
atoms rotate until their little magnetic fields all line up and work together to make a big
magnetic field. A magnet can be polarized even if it cannot conduct.
Dr. Ken Mellendorf
Illinois Central College
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Update: June 2012