New nanoparticle solder alloy (tin is no good)

[RayLopez99]

From Popular Mechanics Feb issue. I bet they still use lead-free tin in most motherboards today...

RL

THE PROBLEM
The move to eliminate
lead from solder (an
alloy used for its low
melting point) over
the past decade was
good for the environ-
ment but bad for short
circuits. Lead-free tin
solder has the strange
habit of growing
“whiskers”—filaments
that extend, causing
shorts. Tin whiskers
led to a diode failing
at a nuclear plant in
Connecticut in 2005.
THE SOLUTION
Lockheed Martin
developed a printable
nanocopper solder
paste that isn’t
subject to whiskering.
Copper conducts
electricity 10 times
better than tin
solder does, but its
melting point of
nearly 2000 F makes
it too hot to use on
circuit boards.
Research ers found
that working with
copper nanopar-
ticles—less than 10
nanometers across—
dropped the melting
point to less than 400
F, making a perfect
nanocopper solder.
— ALEX HUTCHINSON

 

[David]

At Mon, 06 Jan 2014 22:51:03 -0800, RayLopez99 rearranged some electrons
to write:

From Popular Mechanics Feb issue. I bet they still use lead-free tin in
most motherboards today...

RL

THE PROBLEM The move to eliminate lead from solder (an alloy used for
its low melting point) over the past decade was good for the environ-
ment but bad for short circuits. Lead-free tin solder has the strange
habit of growing “whiskersâ€â€”filaments that extend, causing shorts. Tin
whiskers led to a diode failing at a nuclear plant in Connecticut in
2005.
THE SOLUTION Lockheed Martin developed a printable nanocopper solder
paste that isn’t subject to whiskering.
Copper conducts electricity 10 times better than tin solder does, but
its melting point of nearly 2000 F makes it too hot to use on circuit
boards.
Research ers found that working with copper nanopar-
ticles—less than 10 nanometers across—
dropped the melting point to less than 400 F, making a perfect
nanocopper solder.
— ALEX HUTCHINSON

If you read the actual news release from LM, you will find (1) this is
more than a year old (24 OCt 2012) and (2) there are unsolved technical
issues, such as bond strength (the only challenge they specifically
list).

So, definitely not ready for the military market, much less the
commercial market.