Hmm, not sure of this

A team led by Prof. Hanchen Huang of Northeastern University has discovered a new way to merge metals at room temperature, without heat by developing a new material called ‘MesoGlue’. Soldering techniques have improved a lot and in large scale circuit board production, most parts of it have been automated. But one thing has remained unchanged throughout the evolution of circuit boards; the hot solder. There has never been another way to attach electronic components to a PCB without melting iron.

Err, no, you don’t melt iron to make solder. Tin or bismuth, maybe.

But this:

MesoGlue is a combination of metal and glue. The creators have used metallic nanorods with cores coated with elements Indium and Galium on either side of the two surfaces that need to be joined. When the two surfaces come in contact, the nanorods are interlocked, and form a liquid which is solidified by the core of the rods.

That sounds interesting. Ga melts at just above room temperature. And I think I’m right in saying that some In/Ga mixtures are liquid at room temperature. Think, not sure.

If I’m right about that then this is an interesting exploitation of a known effect, rather than something entirely new. And also as such that patent it going to be pretty limited in its application.

I’d also be very wary of predicting widespread adoption.

Tin is, umm, $20k a tonne these days? Ga is $500k a tonne, In $800k? All numbers from imperfect memory but about right I think. Have to be a hell of a performance upgrade to justify those costs. And then of course there’s supply: there’s again from memory, some 50k tonnes of Sn a year used, global production of Ga is maybe 400 tonnes, Indium not a great deal more.

Wouldn’t say this is going to go mass market right now really.

14 thoughts on “Hmm, not sure of this”

  1. ” There has never been another way to attach electronic components to a PCB without melting iron.”

    Sounds like they’re saying that other than soldering, there’s no other way to attach things to a PCB that doesn’t involve melting Iron, which I guess may be accurate.

  2. Conductivity? A solder joint isn’t going to have all sorts of exciting semi-conductor properties.

    Also, if this neatly glues at room temp, how stable is the join to changes in temp?

  3. Conductive glue is nothing new.

    Based on the graphics accompanying the article I’m not entirely sure what is supposed to be happening. Interlocking combs with a liquid alloy between them somehow stick together. I can only guess that is is surface tension of the alloy or maybe on a small enough scale to work like van de Waals force does with gecko feet?

  4. In the first part, if you substitute soldering iron for melting iron (assume a mistranslation) it makes a bit more sense.

    Unless the glue somehow dries in air I can’t see how this would work outside of a lab.

  5. Sounds like they’re saying that other than soldering, there’s no other way to attach things to a PCB that doesn’t involve melting Iron, which I guess may be accurate.

    Bolt and nut does fine for power transistors, transformers etc. Clips do fine for smaller components.

    The thing that concerns me is why “melting iron”? Why not melt something easier – gold or silver would do and are better conductors than iron. Even copper melts at 1000C rather the iron at 1500C. Although, once you get to needing those sorts of temperatures, you’d need to be very careful to prevent damage to the PCB itself.

  6. For those of us of a certain age, we used to use breadboards, and for one off bits of service kit like servo writers, remained so rather fabricate to pcb.

  7. Nice trick… But last time I checked you want your connections and joints to be as conductive as possible, so achieving connection with a *semi*conductor is somewhat… useless?

    And I share Tim’s concern about the temperature range. There may be whatever forces at work even when the stuff turns liquid again, but most electronics are in an environment with vibration. Stuff *will* shift if the connection isn’t a solid up to well above operating temperature.

  8. Interesting-
    I’m thinking there is a language thing going on here. When he says “melting iron” I think he means either “soldering iron” or “melting metal”. Essentially what this seems to be is a conductive glue. Apparently what’s new is that it is conductive thermally as well as electrically, and the electrical conductivity is as good as solder.

  9. I’m going to guess that however wrote this either doesn’t speak English as a first language or has no technical background due the melting iron line.

    “The creators have used metallic nanorods with cores coated with elements Indium and Galium on either side of the two surfaces that need to be joined.” The price and current usage of Ga/In are nice to know but what we don’t know is how much is actually used in this process. What the nanorods are made of is never stated.

  10. My father in law had patents out years ago for “conductive glue” he spent quite as bit of time working with Scandinavian companies as a consultant developing it. Eriksson and Nokia come to mind for some reason. The patents ran out about 15 years before he died about 10 years ago.

    Daedalus.

  11. Bloke in Costa Rica

    My guess for the ‘melting iron’ thing is a bit of pidgin creeping in during the translation. They probably meant, “without a soldering iron”. English has a particularly rich vocabulary when it comes to tools and so forth. In Spanish, one word, soldar, has to do triple duty for welding, brazing and soldering.

    As for the invention itself, sounds like bullshit. It was bad enough when they stopped using lead in solder. Leading up to this a couple of decades ago industry was shitting itself. It’s all very well if your microburst Doppler radar conks out because of tin whiskers – you can replace it and probably only a few planes will crash. But if the 2nd IF stage on a transponder on a commsat goes tits up it’s not like you can send a bloke to fix it. This stuff will never get cleared for aerospace use.

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