Thank christ, have you tried to source NdB magnets at quantity lately? I hope these get to be produced at scale soon, although unfortunately it sounds like the technology has been "exclusively licensed," which in my experience means a 500% markup from whatever its aiming to supplant once it finally hits production. The price of progress, I guess.
But yeah, I tried to order a few hundred rare earth magnets from China (where almost all of the world's rare earth metals come from) and got told that they can't export "pill-shaped" objects...bullshit, that's the same mealy-mouthed politically-backed excuse that they gave for not shipping a few dozen CCP badges through customs.
Maybe someone who knows more about...all of this...can correct me, but tl;dr: Take an iron wire or sheet of diameter/thickness ~10μm-1mm. Strain it by pulling it in opposite directions, e.g. using two rollers pulling in opposite directions. While the iron is strained, heat it to ~125-600C in an atmosphere of N2 or N2+inert gas at ~0.15-1.5 Pascals for 2-10 hours. You actually need atomic Nitrogen and this part of the patent is vague, but I think ~500C might be enough to break the N2 bonds? They also describe a urea infusion process, but that sounds more difficult for a garage effort. Anyways, if that all works, it sounds like you can stack 'em to make larger and more powerful magnets. Anyone up for it?
There's a lot of canceled items in the patent, I wonder if that's because it was too vague to be part of the patent? I agree with your interpretation of the manufacturing process. They expose the sheet of <001> Fe to either nitrogen gas (N2) or NH3. NH3 does break apart with high temperature but ideally you want to work with N2 instead for safety reasons. It's more efficient to break the N2 bond using a cracking source, they use a plasma arc to break the bond of N2.
The usual problem is always going to be compositional control, you know, coming up with a method that preserves the rather excessive stoichiometry of Fe16N2. There's a bunch of other phases that can be achieved with simpler stoichiometries, so the long term stability of this magnetic phase is of concern to me. What are the ideal operating conditions of this magnet before interdiffusion occurs and we lose the right stoichiometry? Maybe there's a small window that could render this material inapplicable to many mechanical or thermal conditions.
Oxidation of the Fe sheet before nitridization is another concerns. Fe oxidizes very easily and would become a barrier for the nitrogen.
The other concern is that they characterize the magnet's performance only on the product of saturation magnetization and coercivity, and mention using ion bombardment to enhance the coercivity. This can be interpreted to mean that the Fe16N2 has a poor coercivity which means that it's a magnet that is very easy to switch with weak magnetic fields or thermal energy. Not what you want for permanent magnet applications.
So I still have a lot of questions and concerns although I do think it's worth pursuing this material because it makes a lot of financial sense as Fe and N are super common and easier to process.
But yeah, I tried to order a few hundred rare earth magnets from China (where almost all of the world's rare earth metals come from) and got told that they can't export "pill-shaped" objects...bullshit, that's the same mealy-mouthed politically-backed excuse that they gave for not shipping a few dozen CCP badges through customs.
Anyways, the patent application doesn't make it sound THAT hard. Maybe it's something you could DIY for personal use: https://google.com/patents/US20140299810
Maybe someone who knows more about...all of this...can correct me, but tl;dr: Take an iron wire or sheet of diameter/thickness ~10μm-1mm. Strain it by pulling it in opposite directions, e.g. using two rollers pulling in opposite directions. While the iron is strained, heat it to ~125-600C in an atmosphere of N2 or N2+inert gas at ~0.15-1.5 Pascals for 2-10 hours. You actually need atomic Nitrogen and this part of the patent is vague, but I think ~500C might be enough to break the N2 bonds? They also describe a urea infusion process, but that sounds more difficult for a garage effort. Anyways, if that all works, it sounds like you can stack 'em to make larger and more powerful magnets. Anyone up for it?