Making new m31 to fill the shortage

edited March 2016 in Magnets
To fill the shortage of M31s I ordered some magnets that are nickel coated 3 mm x 1 mm Disk magnets and have talked to a company that does medical grade titanium nitride coatings. I am going to have two magnets coated as a test to see if this is a viable option. Does anyone see why this would not work? Or any reason why this would not be safe to implant?


  • I believe the general consensus is that a nickel plated magnet is a no-no. If the TiN layer fails while it is inside of you then your body will be exposed directly to the nickel. It won't kill you obviously, but your magnet will probably reject, which could lead to all sorts of other bad things.

    With this sort of thing, redundancy is key. The more bio-safe layers, the better. It would be helpful if you could start off with a gold plated magnet. Perhaps you could have more than one layer of the TiN coating as well.

    I am no expert though.
  • @cassox do you think this will work?
  • @chrisbot The guy at the plating company was planning on coating one side, flipping it over, then coating the other. That means that theoretically the sides have two layers however as you said if the ends fail that could be an issue.
  • @Youdontunderstand
    Think about it like a shadow, the coating can't reach the other side and that is why he plans to flip it over. How much worse is nickel than neodymium? I don't know, but I would not want to find out. Things we say like that comes from experience and multiple points of views. Hence why I prefer something I can verify on this bored vs something I read off of google.

    John Doe
  • Ni-Cu-Ni will introduce heavy metal poisoning via nickel saturation, which usually results in heavy localised swelling, pain, pus buildup... it's really nasty.

    NdFeB failure isolates twords the Boron exposure moreso than anything... I think... don't quote me on that. but also very bad for you. Also very painful. 

    ANY coating failure is unideal and adds up to failure and rejection in the same manner. Never plan for it or allow for it to be a condition or situation that is taking place, the intent should always be as perfect as possible for the application.

    In regards to TiN;

    If i understand correctly, you want a single, medium thickness coat of Titanium nitride. A thicker coat allows the coating to flake and become weaker than a coat with less bulk that does not start getting weird layering. I THINK with the same logic, you also only want a single coat, not multiple layers of coating, if you will, on TiN.

    I know Parylene and Au love to work together. I do not know if Au+TiN would be a good idea, given how soft Au is. The trick is you want a REALLY firm layer to bond that TiN to, if the TiN fails and actually gets damaged physically, the magnet is probably compromised no matter whats under it. (excluding diamond... Looking at you Cassox, with your prototype Diamond/TiN fancy magnets D:>)

    The weakest parts of these coatings is the edges, again, if I understand correctly, moreso than the flats. Too thin of a coating will cause pin-holeing, which also will allow the coating to be bypassed and the delicious Ni-Cu-Ni layer to get leeched out, which is coating failure. x-x

    TiN also needs to be applied without high temperatures in a vacuum. @Chironex would probably have fun telling you what this is like, but really, go read around some of his threads, it's informative. ^^

    Parylene is another magnet combination... Those are primarily short-term magnets, they aren't ideal for long term, leaving in for years at a time.

    But back to Ni-Cu-Ni vs NdFeB... if you CAN have a magnet coated in TiN WITHOUT the Ni-Cu-Ni layering, those would be superior due to lack of 'dead material' not contributing to magnetic strength. Coating thickness is huge because of volumatic expansion.

    Amal @ DangerousThings and Alex @ Cyberise are both working on TiN M31 supply. A couple of people are playing with a couple new coatings as well. By the time these get through to fill the shortage, the shortage may be over, but again, don't quote me on this. ^^'
  • PVD deposition via plasma, a vacuum is drawn and nitrogen is back flown into it. Then a magnetron is turned on creating ions (plasma) said ions hit the target and tear off little pieces with, some of which land on your target. As for coating thickness to thick will be flakey and two thin will have what are called pin holes, pin holes are created when the TIN cools and shrinks as a result. Those the magnet is exposed in a lot of places. How were you planning to test these magnets?

    John Doe
  • @Johndoe Thank you, I always get to remembering PVCD, then forget everything else as far as technical names for the parts and processes. X_X

  • @johndoe I was planning on dropping the magnets into a nickel indicator solution to see if the layer below the TIN was exposed
  • Also for those who may be able to answer would demagnetization be possible in the high temperatures of TIN coating?
  • edited March 2016
    Easily. Very easily.

    I don't remember the exact threshold off hand, but I know autoclave will critically damage a magnet's integrity as far as coating goes from thermal expansion, disregarding gauss reading. It does mess with gauss, too. Magnets cannot be Autoclaved, yet alone PVD coated.

    But heat is very dangerous for NdFeB. That's a very real issue to deal with when coating, keep it cool/cold/not hot. >~<
  • Keeping it cool is the million dollar question. I have been researching this sense December and am just getting to the point ware I feel I know enough to do this. I seldom advocate against a idea but I think you should just wait or keep asking questions before spending any money. Plus you seem to be trying to do this on the cheep am I wrong? Are you a ware there are off the self magnets available? I don't know if they still make them, but there are magnets that come coated in stuff that we have sense developed/evolved (depending on the glass) beyond leading to TIN. My point still stands wait it out and read up before diving head first into this type of stuff, I did and had I gone through I would be dead.

    John Doe
  • All i can say is i wish you the best of luck. Its not impossible. Plenty of people have m31s.. but getting a perfect coating during manufacturing is so hard. Ive tried out like 10 companies and a miriad of fixturing solutions. The edges are nearly always an issue or you end up with pinholing.

    Nickel sucks but if you had an adequate tin i wouldnt worry about it. If you go ahead let me know. Ill send you some of the nickel exposure solution i use.
  • Youdontundedstand and I are shipping magnets to coating companies as we speak.
  • If you'd like to Skype about this someone this week let me know. I've worked hard on this stuff. Maybe I can help a bit.
  • What about a barrel plating system? That way the coating should be even, with no issues on the edges. That means ofcourse the barrel needs to be submerged in the solution and rotated.

    Not to familiar with the bio compatible plating solutions, but should be one that can be used like this?
  • edited March 2016
    PVD method is the name of the game here, I'm not sure if there's a method to liquidise it. >~<
  • Long time lurker, first time poster, is there any way I can help get these bad boys back in the market? I've been wanting an m31 for a really long time, found a location that would implant them and bam, no dice, out of stock. I may have some resources that could help, just gotta know what's needed.
  • You can just sputter it.
  • I'm all ears for this, I've been looking all over the place for a coating company here in the US and none of them are willing to coat magnets in TiN.
  • Can't TiN be electroplated?
  • edited March 2016
    So here's what I was thinking, we can get a custom magnet like these guys ( that is designed to susped our uncoated m31s even a few millimeters above in air. Combine this with a liquid coating method and the magnet can be suspended in the solution allowing an even coat without marks from a fastener. Seeing as the company mentioned above can print magnet faces at a pretty high resolution, it's very possible to have a mixture of north and south poles on the same face that are able to levitate the m31 with ease. What do you think?
  • @ElectricFeel my bad, I didn't notice the formatting got all messed up on mobile. I got it fixed now.
  • I can't imagine what would happen if this fails inside me

    I got a severe nickle allergy (so bad I can't wear metal belts, I start bleeding at the end of the day)

    such an allergen inside the body, sounds .... scary
  • Likely it would swell up your entire hand and cause you to go to the ER with risk of you losing said digit.  People like you are actually the reason that I've been researching the possibility of growing bone around implants.

    Confession:  I have this same allergy.
  • Long time lurker, newly approved member, first time poster:

    As mentioned before, doing the TiN coating on either a bare or tin-coated surface would make for a very bad worst-case scenario should the coating fail. However, I do have a thought or two, aswell as a question (bottom) here:

    Would it be possible to perhaps use a very thin layer of gold plating sandwiched between two layers of TiN, or would that perhaps have too many negative consequences with regards to the mechanical and magnetic properties?

    If this could be done it would not only give you a comparatively safe, protective boundary layer should the top coating fail, but also include a "fail-safe" (now free from leaks to an acceptable degree of certainty, right?) bottom layer underneath that should be, theoretically, very durable?
    And even if this bottom TiN coating should include some pinholes, these would likely be made quite leakproof by the gold on top, somewhat like the tar coat applied onto wooden ship hulls?

    This three layered approach would also have the added benefit of (and please correct me if I'm dead wrong here) making it possible to (accurately) inspect at least the top TiN layer for pinholes etc using a small Tesla coil? I'm fairly certain this should be possible, in theory at least, given:

    The top coating isn't too thick. (check?)
    Enough difference in the electrical conductivity of the two materials (check?) Where the sub-layer should preferrably conduct more readily (check?)

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