Is neodymium naturally magnetic?

[kolleamm]

Also does it make a better core for an electromagnet than iron does?

 

[davenn]

Also does it make a better core for an electromagnet than iron does?

from wiki

Neodymium is a metal which is ferromagnetic (more specifically it shows antiferromagnetic properties), meaning that like iron it can be magnetized to become a magnet, but its Curie temperature (the temperature above which its ferromagnetism disappears) is 19 K (−254 °C), so in pure form its magnetism only appears at extremely low temperatures.[5] However, compounds of neodymium with transition metals such as iron can have Curie temperatures well above room temperature, and these are used to make neodymium magnets.

note it is only naturally magnetic at extremely low temperatures
This is why Nd magnets are a mix of Nd Fe ( Iron) and B (Boron)
Also note that Nd does not occur naturally as a metal, it needs to be refined out of the ores that it is present in

and to answer your specific Q ...

Also does it make a better core for an electromagnet than iron does?

no, it oxidises VERY quickly, even when mixed with iron and boron
it's also toxic and flammable at temps as low as 150C



Dave

edited to fix spelling and grammar

 

[kolleamm]

from wiki



note it is only naturally magnetic at extremely low temperatures
This is why Nd magnets are a mix of Nd Fe ( Iron) and B (Boron)
Also note that Nd does not occur naturally as a metal, it needs to be refined out of the ores that it is present in

and to answer your specific Q ...


no, it oxidises VERY quickly, even when mixed with iron and boron
it's also toxic and flammable at temps as low as 150C



Dave

edited to fix spelling and grammar

Thanks a lot! That pretty much sums it all up.

 

[strangerep]

no, [neodymiun] oxidises VERY quickly, even when mixed with iron and boron
it's also toxic and flammable at temps as low as 150C.

Hmm, now I understand why these very strong permanent magnets have to be encased in nickel.

(I bought one some years ago and it still seems to be as strong as ever.)

 

[davenn]

Hmm, now I understand why these very strong permanent magnets have to be encased in nickel.

Yup, I have a cylindrical one here (1/2 " dia. 1" long) that a little of the nickel plating has peeled off and the Nd mix below is oxidising nicely

D