My company is specialised in Earphone and the magnet NdFeB is in used. The Spec is like this OD 5 x ID 2 x 1 mm, BH(max)kj/m3: 263~279, Br: mT(SI) 1.17~1.22, Hc: kA/m 860 MIN, Ep-REFe by Zn or CU+Nib. I am curious about the Al-Ni-Co magnet,if i change to Al-Ni-Co, does the magnet’s feature stay the same? its cost would be higher or lower? if Al-Ni-Co can not, which kind of compound can replace it?
I also noticed that in the material code of the magnet there are usually some letters such as: H, UH etc… Is this temperature related?
Last thing, is the Sm-Co magnet (as posted in some websites) the highest price (even higher than Nd-Fe-B)?
If you can tolerate a 5 to 10% reduction in performance, SmCo may be an option. Currently it is cost-effective with NdFeB. One other benefit: SmCo wouldn’t need any corrosion protection in that application.
Fe-Cr-Co does not have sufficient coercivity to work in your application.
The H, UH, etc letter codes refer to the intrinsic coercivity of the NdFeB material. Generally H means a minimum intrinsic coercivity of 17 kOe, SH for 20 kOe, UH for 25 kOe and so on. The higher the intrinsic coercivity, the higher the operating temperature.
Up until a few months ago, SmCo was one of the most expensive magnetic materials. However, the recent price spikes in the raw material for NdFeB has changed this. Things may revert, but at the moment, SmCo is cost competitive with NdFeB if your application requires magnets with energy product in the 30 to 32 MGOe range (237 to 252 kJ/m^3).
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