Iron nitride permanent magnets made with DIY ball mill [video]
youtube.com

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109 points

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xqcgrek2

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17 days ago

33 comments

bkraz ・ 15 days ago

I always enjoy seeing one of my videos on HN! Let me know if you have questions.

  • pierrekin ・ 15 days ago

    Not strictly related to this video - sorry about that - but I have some ideas of how to improve the system you used to record arc welding in high quality.

    Do you still have the hardware? Does revisiting the project and using some signal processing to try and extract color images sound like fun? I would be excited to collaborate on this if you had energy for it!

    • bkraz ・ 15 days ago

      You should definitely contact Kron Tech (makers of the system -- let me know if you want an introduction). I have some interesting image processing videos coming up -- nothing to do with color reconstruction, but that also sounds good. My project pipeline is pretty full, but I will let you know when I am adding new ideas.

      • pierrekin ・ 12 days ago

        Thank you for your kind offer to introduce.

Animats ・ 16 days ago

So what happened with the startup, Niron? [1] They've been trying to commercialize this for years.

[1] https://www.nironmagnetics.com/

  • londons_explore ・ 16 days ago

    The fact they don't have a 'buy one of our magnets now, $10' button tells me that the tech doesn't actually work.

    • scythe ・ 15 days ago

      The only report of a bulk Fe16N2 magnet I remember reading about used a 2 GPa (300 kpsi) diamond anvil to compact the powder. I can see why that might be economically impractical right now.

      Also there was a bombshell paper that came out claiming synthesis of bulk L10-FeNi which was later retracted [1] and may have put a temporary damper on interest in Fe16N2. It remains unclear which material will be available first.

      1: https://advanced.onlinelibrary.wiley.com/doi/full/10.1002/ad...

      • londons_explore ・ 15 days ago

        2GPa wouldn't be hard to achieve in a production setting, as long as it's only needed for a second or two. You simply have a diamond anvil in your factory.

        Or alternatively, you use explosives or shock waves to very briefly get the pressure needed.

    • ralphonzathew ・ 16 days ago

      Iron nitride is much more useful as a thin film coating. Bulk magnet tech just isn't there.

JKCalhoun ・ 15 days ago

He's like the old "Amateur Scientist" column from Scientific American magazine come to YouTube.

daveguy ・ 15 days ago

It would be interesting to compare the iron nitride magnet sample with an just epoxy + iron filings. I would expect iron to have some area between the curves because iiuc iron is able to hold a magnetic charge.

  • bkraz ・ 15 days ago

    I measured the pure iron powder as well. It shows no measurable area inside the BH curve, which at first seems incorrect since the textbook retentivity value for pure iron is fairly high. The textbook may be referring to a single iron magnetic domain. In a practical sample (even a solid piece of iron, let alone powder in epoxy), there are likely many magnetic domains that cancel each other out, and "soft iron" is used commercially for the very reason that is has extremely low retentivity in bulk.

kragen ・ 15 days ago

My bookmark from May 28 says:

https://www.youtube.com/watch?v=M6XIgdS1rzs #Applied-Science #video on #bootstrapping “insanely powerful” planetary ball mill grinder to make α'' iron nitride filled epoxy for magnets, which did work somewhat; he tested it in a 1.6-tesla vibrating sample magnetometer he built using a lock-in amplifier to plot its B–H curve.

Hopefully this summary is useful to others.

On the topic of alternatives to rare-earth magnets, their most important use is probably electrical machines (motors/generators, and switched reluctance electrical machines can supposedly have power densities comparable to rare-earth-magnet permanent-magnet electrical machines, and you can build them out of just punched electrical steel, copper or aluminum wire, and insulator, just like a line-frequency power transformer. (I suspect Metglas would work better than electrical steel, without requiring any strategic materials, but might be impractically expensive.) Some relevant bookmarks from September 22:

https://www.youtube.com/watch?v=TAhF45AtsgA #video by #Akio showing his Arduino-driven switched reluctance motor #electronics control board and working motor #hardware

https://www.youtube.com/watch?v=vvw6k4ppUZU #video about "SynRM" switched reluctance motors made out of sheets with slots punched out to follow field lines. Low-quality AI voiceover from #Lesics.

(You can actually build SRMs out of non-laminated mild steel and speaker wire or whatever, but I think they won't be efficient.)

Another related bookmark from today:

https://www.youtube.com/watch?v=RAQexymmt64 lecture #video from 02012 (? or 02019?) by JR Hendershot about #switched-reluctance motors (“reluctance synchronous motors”) mentioning ABB’s new #SynRM product line (17–350kW), mentioning higher torque density than induction motors (which use the exact same stator design) and lower cost than permanent-magnet electrical machines as key advantages. Cites a price spike in neodymium as a key reason for interest in the area, which makes me think it’s from 02012 rather than 02019, when it was uploaded to YouTube. It actually says that “reluctance synchronous” motors are different from “switched reluctance” motors. Shows little webs in the stamping to hold the flux carriers together in the transversely laminated anisotropy rotor. Shows ABB’s plot of efficiency over its product line, ranging from 88% at 1kW rated power up to 97.5% at 700kW, because of the missing ohmic losses in the rotor relative to an induction motor. Boglietti and Pastorelli’s paper from 02008 reports 17% higher torque for an SRM (RSM) version of an existing induction motor. Shows some asterisk-shaped switched-reluctance rotors (using higher frequencies) and contrasts with RSMs’ trippy rotor design (using the same inverters as for an induction motor). Also has some nice electronics schematics. “The key to the improvements in efficiency and power factor lies in the inductance ratio or the saliency ratio in the d [direct] & q [quadrature] axes.”

wolfi1 ・ 16 days ago

good luck getting ammonium nitrate without being visited by the police (at least here in Europe)

  • Calwestjobs ・ 16 days ago

    yeah, but point is more like that we do not need hard to refine ( that is why are they called rare earths ) materials from china, if those magnets were strong as neodymium ones. which they are not in video.

    --

    problem with chemistry is most of these things are easily made in garage.

    For example Slovak military is training disposal of homemade explosives / chemicals by watching NurdRage videos ;)

    https://youtu.be/Zybj-mi1FP0?si=KGMUJj5l5NUt2egh&t=68

    or this simple technology from 1890 used in different way is helping helping Europe to be self sufficient with energy:

    https://www.tue.nl/en/research/institutes/eindhoven-institut...

  • metalman ・ 16 days ago

    not that big a deal, but you do have to register and have basic security, ammonium nitrate is by todays standards just one step up from black powder, and if it's a proper company with mechanical and chemical engineers signing off then it's literaly just paper work.All in all industrial type experimenting involves avoiding exuberant exothermic reactions and dramatic kinetic events, with or without an electrical component, just about everyone involved has a story, and there are plenty of injuries and fatalities. One of the hard parts of bootstraping any industrial process is having people who have the knowledge and experience to train people in how to do things and not get hurt, it's not "saftey" as much as survival skills.

    • ahazred8ta ・ 12 days ago

      As Kevin Kelly said about tribal lore: "In many cases the only way to do an experiment safely is to find a more experienced person to help. This is not book-learning, it's your life at stake. There is an unbroken chain of these people leading right back to the first guy who survived, and you want to be part of that chain."

    • HeyLaughingBoy ・ 15 days ago

      > ammonium nitrate is by todays standards just one step up from black powder

      I thought that was potassium nitrate. Which I bought a bottle of on Amazon when I was curing a ham.

      • ridgeguy ・ 15 days ago
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        Didn't know about the use for meat curing. I've routinely bought KNO3 for stump removal.

        • HeyLaughingBoy ・ 15 days ago
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          hmmm. I have lots of stumps, and didn't use that much from the bottle. I think there's some old diesel in a can somewhere...

          • Loughla ・ 15 days ago

            Use aluminum powder instead. Is less messy and easier to set off.

            And it's more fun because it's more of a pop than a push.

  • impossiblefork ・ 16 days ago

    Farmers work with hundred kilo bags of the stuff.

    • wolfi1 ・ 16 days ago

      farmers yes, I wanted to cool some stuff with it, no chance

      • impossiblefork ・ 16 days ago
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        and you can't just buy it for your garden then?

        • numpad0 ・ 16 days ago
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          Fertilizers and a ball mill in a garage is just the classic direct highway route from nothing to pipe bombs, so there are going to be checkpoints along the way.

          • amy214 ・ 15 days ago

            Fertilizers is what we call "a gateway chemical" first thing you're putting some ammonium nitrate on your crops to make more than break-even this year, next thing you know it's a U-Haul parked up in Oklahoma city. We need to have common sense fertilizer control laws. Mostly it will be police who can use fertilizer, sometimes though we'll let a private detective (ex-police) use fertilizer.

  • nancyminusone ・ 15 days ago

    What does your country use for its instant cold packs?