Materials

"Metal glue" could replace welding and soldering – in some applications

"Metal glue" could replace wel...
A CPU bonded to a heat sink, using the new glue
A CPU bonded to a heat sink, using the new glue
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A diagram illustrating how the nanorods interlace and then create a liquid which is subsequently solidified
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A diagram illustrating how the nanorods interlace and then create a liquid which is subsequently solidified
A CPU bonded to a heat sink, using the new glue
2/2
A CPU bonded to a heat sink, using the new glue

Usually, if you want to join two metal objects together, you either weld or solder them – depending on how big they are. Both processes involve the application of heat, however. This can damage the items (in the case of electronics), or even cause explosions (in the case of things like gas pipes). That's why scientists at Boston's Northeastern University created MesoGlue. It's a glue that bonds metal to metal – or to other materials – and it sets at room temperature.

Designed by a team led by Prof. Hanchen Huang, MesoGlue is made up of microscopic nanorods that have a metal core. Some of them are coated with the ele­ment indium, and some with gallium.

The facing surfaces of the two objects-to-be-joined are first treated with these rods. A layer of the indium-coated rods is applied to one surface, while a layer of the gallium-coated rods goes on the other. In both cases the rods stand up from the surface, sort of like the bristles of a hairbrush.

"When you mash the heads of the brushes together, all the little bristles push past each other so the two brushes are basically stuck together," PhD student/co-inventor Paul Elliott explains to us. "The interlacing process is fairly similar in our glue. The bristles are spaced well enough so they can slide or be pressed in between each other."

A diagram illustrating how the nanorods interlace and then create a liquid which is subsequently solidified
A diagram illustrating how the nanorods interlace and then create a liquid which is subsequently solidified

When the indium and gallium on the rods come into contact, they form a liquid. The metal cores of the rods then react with that liquid, causing it to harden into a cohesive solid. This results in a bond that reportedly matches the strength of a traditional weld or solder.

Additionally, unlike those formed by regular polymer-based glues, MesoGlue bonds are thermally and electrically conductive, they aren't adversely affected by heat, they're highly resistant to air/moisture leaks, and they require little pressure when being formed.

"The metallic glue has multiple appli­ca­tions, many of them in the electronics industry," says Huang. "As a heat conductor, it may replace the thermal grease currently being used, and as an electrical conductor, it may replace today's solders. Par­tic­ular products include solar cells, pipe fittings, and com­po­nents for computers and mobile devices."

MesoGlue is now being commercially developed by a spin-off company of the same name. "We are working on turning this into a liquid form that will make the process just like a glue or epoxy that you would use at home," Elliott tells us.

A paper on the research was recently published in the journal Advanced Mate­rials & Processes, plus there's more information in the video below.

Sources: Northeastern University, MesoGlue

MesoGlue Introduction

11 comments
xs400
Better invest in Indium and Gallium, this is going to change the electronics and welding world and many other industries IF it is economically viable, especially for DIYers. Hope it'll be cheap enough for laymen to buy and use.
hkmk23
I am puzzled here, a good idea yes, but you have to "fasten" the rods to the materials in the first place.....so where is the gain?
pmshah
This could have saved me a bundle. Poorly designed hinge pivot on my front loading Whirlpool washing machine simply broke because it was made out of zinc alloy and could not sustain the very heavy weight of the front see through glass window. What the company offered as replacement - out of warranty of course - was even worse. Poorly machined and made from alluminium casting !!! I ended up having to buy a new one.
Mr. Hensley Garlington
That's pretty awesome. Lots of benefits to this method where traditional soldering and welding maybe found lacking for certain applications.
To me its like a metal velcro that melts together when linked up.
physics314
Indium is one of the rarest metals on Earth. I wouldn't hold my breath for it to be used as glue.
Bob Flint
In the case where a permanent bond is preferred, how does it perform in thermal cycling regarding the expansion of different materials such as glass & metals?
It seems that the nano structures are inherent in the adhesive, or the application technique?
Sort of a one way liquid Velcro one type of adhesive for each side, they combine surfaces? Set time?
The electronics are mostly permanent applications, even though the processor may be up-graded, simply replace with a better heat sink.
Martin Hone
The obvious question here is, how does the initial layer get applied to the surface, and how reliable is it ? Ok, two questions, but critical...
StWils
Can other metals or materials offer the same benefits? Can a nano scale adhesive also be undone without toxic or destructive results? Health & Safety issues?
biz boy
I agree with hkmk23. When something mended with epoxy breaks, it is usually the epoxy that hasn't stuck to the surface. This article is missing the most important part, how does it stick to the surface in the first place.
Douglas Bennett Rogers
This might be applied to fibers to reduce pullout length and create a much stronger composite.