a) Coated rods are
arranged along a substrate, like angled teeth on a comb.
b) The teeth are
then interlaced. c) When indium and galium come into contact, they form a
liquid.
d) The metal core
of the rods turns that liquid into a solid. The resulting glue provides the
strength
and
thermal/electrical conductance of a metal bond.
From “Advanced
Materials & Processes,” January 2016
(January 9, 2016) Perhaps
no startup was launched for a more intriguing reason than that of
Northeastern’s Hanchen Huang. From the company website:
“MesoGlue was founded by Huang and two of his PhD students:
They had a dream of a better way of sticking things together.”
Those “things” are everything from a computer’s central processing
unit and a printed circuit board to the glass and metal filament in a light
bulb. The “way” of attaching them is, astonishingly, a glue made out of metal that
sets at room temperature and requires very little pressure to seal. “It’s like
welding or soldering but without the heat,” says Huang, who is professor and
chair in the Department of Mechanical and Industrial Engineering.
In a new paper,
published in the January issue of Advanced Materials & Processes, Huang and
colleagues, including Northeastern doctoral student Paul Elliott, describe
their latest advances in the glue’s development. Our curiosity was piqued: Soldering
with no heat? We asked Huang to elaborate.
On new developments
in the composition of the metallic glue:
“Both ‘metal’ and ‘glue’ are familiar terms to most people,
but their combination is new and made possible by unique properties of metallic
nanorods—infinitesimally small rods with metal cores that we have coated with
the element indium on one side and galium on the other. These coated rods are
arranged along a substrate like angled teeth on a comb: There is a bottom
‘comb’ and a top ‘comb.’ We then interlace the ‘teeth.’ When indium and galium
touch each other, they form a liquid. The metal core of the rods acts to turn
that liquid into a solid. The resulting glue provides the strength and
thermal/electrical conductance of a metal bond. We recently received a new provisional
patent for this development through Northeastern University.”
A schematic
illustrating applications of metallic glue:
a) A CPU on a
printed circuit board connected to a heat sink.
b) A surface
mount device being attached to a printed circuit board.
c) A press-fit
pipe fitting for environments where welding is dangerous or impossible.
d) A glass plate
being attached to metal with a different thermal-expansion coefficient to
cover
a cavity with a
hermetic seal.
From “Advanced
Materials & Processes,” January 2016
On the special properties
of the metallic glue:
“The standard polymer glue does not function at high
temperatures or high pressures, but the metallic glue does. The standard
glue is not a great conductor of heat and/or electricity, but the metallic
glue is. Furthermore, the standard glue is not very resistant to air or gas
leaks, but the metallic glue is.
“‘Hot’ processes like soldering and welding can result in
metallic connections that are similar to those produced with the metallic
glue, but they cost much more. In addition, the high temperature
necessary for these processes has deleterious effects on neighboring
components, such as junctions in semiconductor devices. Such effects can
speed up failure and not only increase cost but also prove dangerous to users.”