This is unexpected to say the least. Of course we may have a
solution now in search of a problem. Yet it is very intriguing and
suggestive.
This also informs us that any substance that is stable chemically can
be melted and set up as a glass to allow a useful revisit regarding
its properties.
Better yet it may be possible to so float extremely thin layers of
such glasses, chemically alter them and perhaps even partially
shape them in this way. All this is important for the ultimate
manufacture of multi layered structures for the future aerospace
industry.
All good.
Modern-day
alchemists turn cement into metal
By Sebastian Anthony
May 28, 2013
It’s not quite lead
into gold, but a team of international researchers have succeeded in
turning cement into metal. This metallic form of cement, which is
electrically conductive and has increased corrosion resistance, might
find applications in protective coatings, thin films (think LCD
monitors), and computer chips.
Cement, which usually
consists of calcium oxide and other common minerals such as silicon
dioxide and aluminium oxide, is of course an insulator. To turn
cement into a metal, the researchers heat the powder to 2,000 Celsius
(3642F) with a laser, turning the powder into liquid. A fantastic
device called an aerodynamic levitator, which uses nozzles pumping
out inert gas to levitate a material, is then used to levitate the
molten cement. The levitator prevents the molten cement from touching
the walls of the container, preventing unwanted crystal formation.
Different gases are introduced into the chamber to modify the
chemical bonds that formed as the liquid cement cools into a glass.
Electrons (the blue
blobs) trapped inside calcium oxide cages
The result is a
calcium oxide/aluminium oxide glass that is structured in such a way
that free electrons are trapped inside cages made of calcium oxide.
These trapped electrons allow for conductivity, much like the “sea”
of electrons in a conventional metal. This phenomenon of trapping
electrons inside a crystal’s structure is fairly new, and this
work, carried out by Chris Benmore of the DoE’s Argonne National
Laboratory and Shinji Kohara from the SPring-8 synchotron in Japan,
along with a handful of European material scientists, is the first to
clearly confirm, define, and image the electron trapping. Previously,
this electron trapping had only been observed in ammonia — but now
that the scientists know how to turn solid insulators into
room-temperature semiconductors, some interesting innovations could
emerge.
As you’ve probably
surmised by now, this special cement isn’t a metal in the copper or
iron sense of the word. Rather, the metallic cement is closer to a
semiconductor, such as silicon (which, in case you were wondering, is
a metalloid). In some ways, though, being a semiconductor is actually
more useful. Already the scientists are speculating that
semiconducting cement could be used as thin-film resistors in LCD
displays. If the special cement can be mass produced, it’s easy to
imagine it being used as a protective coating that also serves some
kind of conductive purpose (in a connected smart home, perhaps?)
Perhaps more importantly, though, it will be interesting to see if
this new process can be used to turn other normally-insulating
materials into semiconductors.
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