Degaussing AlNiCo Magnets

[Rileyesi]

I need to degauss some AlNiCo magnets. They are cylindrical (2" OD, 1.5' ID,
and 1" long). We charge them with a single pole going through the diameter. I
want to degauss about 100 magnets that have been charged, but were left hanging
on a metal plate for years and have lost some of their charge.

Any tips or hints on how to build a degausser? Or, can anyone recommend a
company that makes them? I did a search at thomasregister.com, but most of
those companies make the degaussers for computer monitors. Not what I need.

Thanks.

 

[Mark Fergerson]

Rileyesi wrote:

I need to degauss some AlNiCo magnets. They are cylindrical (2" OD, 1.5' ID,
and 1" long). We charge them with a single pole going through the diameter. I
want to degauss about 100 magnets that have been charged, but were left hanging
on a metal plate for years and have lost some of their charge.

Any tips or hints on how to build a degausser? Or, can anyone recommend a
company that makes them? I did a search at thomasregister.com, but most of
those companies make the degaussers for computer monitors. Not what I need.

If you're planning to charge them, you must have a
furnace available capable of reaching their Curie
temperature (around 800C- 900C for most alloys). Simply hold
them there without an impressed field long enough for their
domains to randomize. For that matter, just heat them above
their Curie point and remagnetize them the way you want.

Googling alnico +demagnetizing returned (among others) this:

http://www.maginst.com/specifications/580_magnetreater.htm

Mark L. Fergerson