Australian scientists accidentally engineer one of the world's most thermally stable materials. It doesn't expand even when heated by 1,400 °C
The composite material could prove particularly useful in aerospace where temperatures can spike wildly between space and atmospheric re-entry.
Researchers at the University of New South Wales (UNSW) in Australia were performing battery-related research when they accidentally discovered that a composite material they were working with had a phenomenal ability to resist heat. The composite material did not change in volume at all at temperatures ranging from 4 to 1400 Kelvin (-269 to 1126 °C, -452 to 2059 °F). It may very well be the most thermally stable material in the world.
This wonder material doesn’t break a sweat even at temperatures well past the boiling point of some metals
In elementary physics, we were told that as a material’s temperature increases, so does its volume. This phenomenon is known as thermal expansion. This thermal expansion or contraction is proportional to the change in temperature and is mitigated by thermal expansion coefficients typical of every material. For instance, with the same temperature increase, aluminum expands more than copper, which in turn expands more than gold, which expands more than iron, and so on. In response to temperature, it is normal for material to also suffer alterations in other properties, such as strength, toughness, or elasticity.
However, some materials are thermally stable, meaning they can retain their properties at required temperatures over extended service time. Extended thermal stability at high temperature is particularly desirable in the automotive, marine, and aerospace industries.
One of the most promising thermally stable materials in the world was recently reported by a team of researchers led by Professor Neeraj Sharma of the University of New South Wales. Using state-of-the-art instruments such as the Australian Synchrotron and Australian Centre for Neutron Scattering at the Australian Nuclear Science and Technology Organisation, the researchers showed that a zero thermal expansion material made of scandium, aluminium, tungsten and oxygen did not change in volume even when it was heated by nearly 1,400 °C.
Writing in the journal Chemistry of Materials, the authors reported only minute changes in the bonds and rotations of the atom arrangements in the structure of Sc1.5 Al0.5W3O12 . The material is easily synthesized and the high availability of alumina and tungsten oxide may enable large-scale manufacture for use in high-precision mechanical instruments, control mechanisms, aerospace components and medical implants.
Remarkably, the composite material’s properties were discovered by accident, while the researchers were busy with other work.
“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,” said Sharma in a statement.
Next, Sharma and colleagues plan on teasing apart the individual contribution of each ingredient in the composite material.
“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.”
Correction (June 17, 2021): The original headline stated that the material doesn’t expand ‘up to 1,400 °C’. The material doesn’t expand over a temperature difference of 1,400 °C, however at a nominal temperature of 1,400 °C it may lose it’s properties. We regret the error.
