In Layman's Terms: Permanent Vs. Rare Earth Magnets

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Skip to content In Layman’s Terms: Permanent Vs. Rare Earth MagnetsIn Layman’s Terms: Permanent Vs. Rare Earth Magnets

January 7, 2011

A lot of confusion arises from buyers of magnetic sweepers and industrial magnetic products regarding the difference between “Rare Earth” and “Permanent” magnets. Technically, Rare-earth magnets are permanent magnets. The primary difference being that rare-earth magnets are made from alloys of rare earth elements while other permanent magnets are ferrite or alnico.

When manufacturing permanent magnetic industrial devices such as magnetic sweepers, magnetic brooms and tow behind magnetic sweepers, virtually all companies use what is known as either Grade 8 or Grade 5 permanent ceramic magnets. There are various grades available ranging from Grade 1-8 however Grade 8 is the strongest type and possesses the necessary properties for manufacturing magnetic sweepers such as a broader “depth of reach” than rare earth making them highly effective for “sweeping” purposes. In contrast, permanent lifting magnets will use the rare earth magnet for it’s immediate surface strength and high resistance to demagnetization. Lifting magnets need immediate “force” at the surface as opposed to a “depth of reach” making rare earth preferable for lifting magnet applications.

When researching various magnetic sweeper related products, it is virtually impossible to tell weather a company is using the strongest Grade 8 magnet or the inferior (and cheaper) Grade 5 permanent magnet. Nearly all of the imported magnetic sweeper products contain the less effective and weaker Grade 5 permanent magnet while any reputable U.S. Manufacuter will utilize only the Grade 8 permanent magnet. While various magnetic sweepers and industrial magnets may look similar, it is best to confirm that the vendor is using a Grade 8 magnet inside!

About the author : Shields Magnetics

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