Identifying a Magnet
Identifying a Magnet
(OP)
I pulled this magnet out of a hard drive that is well over 20 years old. I am having trouble identifying the material and type of magnet. Any thoughts? There is corrosion on all of the sides except the ones that weren't exposed to open air. They are still polished and reflective





RE: Identifying a Magnet
If it is unplated, then it probably is fully sintered SmCo.
Are you trying find a replacement magnet? If so, you'll probably have to send it to a reputable magnet vendor to determine the grade of material and magnetic pattern.
RE: Identifying a Magnet
SmCo5 is most probable.
Atmospheric corrosion in 25 years would be expected. These are reactive materials.
Why are you interested?
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Plymouth Tube
RE: Identifying a Magnet
The color of the magnet indicates that it is nickel-plated, which supports the NdFeB theory. SmCo would not need to be plated.
However, it is still a weird shape - most hard drive voice coil magnets are thin arcs.
RE: Identifying a Magnet
The magnet in the photo was not plated as most Neo magnets are now for use in hard drives. Plating would have remained shiny and the surface is more of a matte texture.
From the shape, I'd say this was from a tall drive, maybe 5 1/4 inch size and full height - something we no longer see.
Early Neo had a problem with oxidation and reaction with moisture to form Neo Hydroxide which is a bluish-gray powder that would be found on the magnet surface. So I'll vote with those who suggested SmCo.
RE: Identifying a Magnet
RE: Identifying a Magnet