That's
a wider range of temperatures, say scientists from the University of New South
Wales (UNSW), than any other material, demonstrated to date, and it could make
orthorhombic Sc1.5Al0.5W3O12 , a very handy tool for
anyone engineering something that needs to work in extremely varied thermal
environments.
Examples
of where this might come in handy include things like aerospace design, where
components are exposed to extreme cold in space and extreme heat at launch or
on re-entry. Famously, the SR-71 Blackbird was designed to expand so much at it is Mach 3.4 top speed that it would liberally drizzle fuel on the runway at
ground temperatures; the fuel tanks wouldn't even fully seal until they heated
up. This new material stays exactly the same volume from close to absolute zero
all the way up to comfortably over the heat you'd expect to get on the wing of
a hypersonic aircraft traveling at Mach 5.
Or there are things like medical implants,
where the range of expected temperatures isn't so varied but even a small
amount of thermal expansion can cause critical issues.
The UNSW team made the
discovery more or less by accident: "We were conducting experiments with
these materials in association with our batteries-based research, for unrelated
purposes, and fortuitously came across this singular property of this
particular composition" says Associate Professor Neeraj Sharma.
After measuring the
material using the Echidna high-resolution powder diffractometer at ANSTO's
Australian Synchrotron and the Australian Centre for Neutron Scattering, the team found an incredible degree of thermal stability. At the molecular level,
materials usually expand because an increase in temperature leads directly to
an increase in the length of the atomic bonds between elements. Sometimes it
also causes atoms to rotate, resulting in more spacious structures that affect
the overall volume.
Not with
this stuff, which the team observed across that huge temperature spectrum
demonstrating "only minute changes to the bonds, the position of oxygen atoms
and rotations of the atom arrangements." The team says the exact mechanism
behind this extreme thermal stability isn't totally clear, but that perhaps
bond lengths, angles, and oxygen atom positions are changing in concert with one
another to preserve the overall volume.
"Which
part's acting at which temperature, well, that's the next question," says
Sharma, who adds, “the scandium is rarer and more costly, but we are
experimenting with other elements that might be substituted, and the stability
retained,”
The other
ingredients, however, are widely available, and bond together using a
"relatively simple synthesis," so the team believes this material
should present no impediments to large-scale manufacturing.
The paper
is available at the journal Chemistry of Materials, and the video below provides an overview of the material.
Source: ANSTO via NewAtlas.com
Element 115 Video:
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