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Iron Nitride Permanent Magnet 1

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Sparweb

Aerospace
May 21, 2003
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Can anyone comment on the validity of the claims in this article, from the University of Minnesota?


Some searching on Google turns up articles that just parrot this one, and some research papers dated from the 1990's.
Is there some reason to think a breakthrough has been made, or is this just the sales staff at UM's technology transfer office polishing an old t***?


STF
 
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No idea how viable their energy product claim is but we do a nitrogen implantation on stainless steels (303, 305) that makes them a pretty good permanent magnet. That is not the intent of the process but it's a handy check to verify the part has been processed. Our process only produces a thin case, about 60 microns deep, they claim to be able to do bulk material.

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Sparweb, the apparent datecode on your link is 2012, so that's 5 years ago to start with. Given that gap in time, no one apparently has seen fit to take them up on their technology. The Wayback Machine caught the page in 2014, so it's at least that old.

Often, the faculty involved will form companies to capitalize on their inventions; the lack of such suggests that the technology had issues.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
The beauty of Fe16N2 lies in its high saturation magnetization, even higher than Fe-Co which has a highest Ms among the commercially available alloys.

The big challenge are the formation and decomopistion of Fe16N2. The conditions (temp, pressure etc.)are very strict to form a pure phase. Most importantly, it is almost limited to thin film and powder. Imagine that it is normal to do a surface Nitrogen hardening, but never heard the whole bulk part can be hardened.

On the other hand, Fe16N2 is a metastable phase, it can decomposite to other phases, so even if you could be able to make a big amount of powder, it is hard to consolidate to full density.

The biggest magnetic challenge is the coercivity, in order to get the claimed 130MGOe, the coercivity needs to be at least half of Bs value, in this case, > 1,2000Oe, plus, the hysteresis loop needs to be square when Hc is only 1,2000Oe. I am not sure if anyone reached a Hc of > 5,000Oe even in the thin film structure.

Being said, I think the potential for a breakthrough innovation exists due to its very high Ms and a high magnetocrystalline anisotropy (for a high Hc). A permanent magnet without rare earth has still been a hot topic.
 
MagBen said:
...A permanent magnet without rare earth has still been a hot topic...
Pot of gold, if you ask me. No more trade restrictions, fluctuating resource prices.
The PR value of getting away from heavy-element mining would be a big attraction, too, to those industries that use magnets for "Green" purposes.

Thanks!

STF
 
Reminds of a time when I worked a company that invested in the "technology of the future" GaAs. 30 yrs later it was still the "technology of the future" and hasn't made much inroads into the realm that was supposedly going to be ceded by silicon when it hit 1-um geometries. So, here we are, pushing at 14-nm technology in silicon that was supposed to be dead by 1980 and no GaAs microprocessors in general use.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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