Demagnetization 1

[prodeng]

Besides heat, is there anything that would make a neodymium magnet lose its magnetism over a 5 year period?

 

[AGuy]

A very high electrical field, over a couple of years, or another neodymium magnet held at close range of similar strength will have an affect.  If the magnets can not get "away" from each other they will cause each other to weaken.

 

[prodeng]

How close is close? In other words, what is considered similar strength, and how close would they have to be to affect the magnetism? [sig][/sig]

 

[bigeasy]

"demagnetization table" i search it...global if you have any tips please let me know.

thanks
bigeasy

 

[drdick]

Physical geometry is a factor. See Domain Theory at

http://www.dextermag.com

 

[gphatch]

Since the actual output of a similar Nd-Fe-B magnet will not be very close to the intrinsic coercive field of the material [a measure of the magnet materials' ability to resist demagnetization], it is unlikely that such a magnet would permanently demagnetize another. However, while in the presence of the second magnet, the first magnet would experience a temporary partial demagnetization. How much, and to what extent, would be dependent on, as DrDick says, the magnet geometry.

 

[mac2]

In addition to the above, a hydrogen rich environment will do the trick also.

 

[gphatch]

A hydrogen-rich environment would cause catastropphic phyiscal changes in Nd-Fe-B magnets within a matter of days or weeks, rather than years. Put it under pressure and you'll see decrepitation of the alloy within minutes and hours. It's one way they use to refine the raw powder used for Nd-Fe-B magnet production.