Neodymium Magnet Properties

This topic has 9 replies, 6 voices, and was last updated 23 August 2016 at 11:10 by Martin Kyte.

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22 August 2016 at 11:50 #24692
Alan Wood 4
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@alanwood4
Volatile ??
Advert

22 August 2016 at 11:50 #251849
Alan Wood 4
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@alanwood4
I had need of a small magnet and had some broken pieces of neodymium that I thought I would file to the required shape.

Now I am not sure if I should have expected it but the file immediately created flying sparks and smouldering filings. Quite impressive.

Probably more effective than flint for those heading to the backwoods and needing to make fire and not having two boy scouts to rub together.

Anyone any knowledge about this property ?

Alan
22 August 2016 at 12:06 #251850
Thor 🇳🇴
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@thor
Hi Alan,

The element Neodynium is reactive, and is used in many products, also as one of the parts in lighter flints – see here.

Thor
22 August 2016 at 12:10 #251851
Alan Wood 4
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@alanwood4
Thanks Thor, perhaps not the best material to be filing.

Have ordered a magnet to size on Ebay …

Alan
22 August 2016 at 12:21 #251852
Martin Kyte
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@martinkyte99762
Machine with diamond tools and cool with fluid or inner gasses to prevent combustion.

Plate after machining to prevent corrosion.

Dust is spontaneously combustable and the evolved gasses are toxic.

Hydrogen is evolved when powder is in the presence of water.

**LINK**

Best to buy the magenets you want really. They are cheap enough.

Martin

PS sound like I know about this but I just looked it up really.
22 August 2016 at 12:59 #251857
Ian S C
Participant
@iansc
I cut some magnets from some old hard drives with the Dremmel with a thin grinding disc, no sparks noted.

Since found a NZ company that manufactures magnets of all types.

Ian S C
22 August 2016 at 18:10 #251897
Bill Davies 2
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@billdavies2
I have found that neodymium magnets, once the surface plating is cracked or damaged, tend to break down fairly quickly, that is, over months. They just seem to crumble, even if not handled. As Thor says above, the material is reactive. I suppose that whatever they are sintered or bound with is minimised for the sake of the magnetic properties. I have considered reinforcing with araldite to get the shape I want, but to make best use of the magnetism requires the attracted part is very close to the magnet.

Bill
22 August 2016 at 18:14 #251898
Bill Davies 2
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@billdavies2
A brief browsing; I'm sure there are many sites, but this gives some interesting info:

**LINK**

Bill
23 August 2016 at 09:21 #251950
Gordon W
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@gordonw
Martin- I don't think " inner gases " would be best for cooling when a lot of sparks are formed..
23 August 2016 at 11:10 #251971
Martin Kyte
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@martinkyte99762
Gordon

Either cool with fluid (not water) or prevent combustion by using Inert Gasses (don't you just hate spelling correcting software). Just a quick precis of the documents in case people did not want to bother looking.

Without the oxygen you don't get the exothermic reaction.

The thing I found interesting was the use of sintering in the presence at high external field to align the dipoles.

regards Martin
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