United States. Researchers at Purdue University have designed ceramic "nanotubes" that behave like thermal antennas, offering control over the spectrum and direction of high-temperature heat radiation.
"By controlling radiation at these high temperatures, we can increase the life of the coating. Engine performance would also increase because it could be kept warmer with more insulation for longer periods of time," said Zubin Jacob, associate professor of electrical and computer engineering at Purdue.
The work is part of a larger field search for a wide range of materials that can withstand higher temperatures. In 2016, Jacob's team developed a thermal "metamaterial," made of tungsten and hafnium oxide, that controls heat radiation with the intention of improving the way waste heat is collected from plants and power factories. A new class of ceramics would expand into ways to more efficiently use heat radiation. Jacob's team, in collaboration with Purdue professors Luna Lu and Tongcang Li, built nanotubes with an emerging ceramic material called boron nitride, known for its high thermal stability.
These boron nitride nanotubes control radiation through oscillations of light and matter, called polaritons, within the ceramic material. High temperatures excite polaritons, which nanotubes, like antennas, efficiently couple to outgoing heat radiation.
Antennas could provide the ability to accelerate radiation, perform improved cooling of a system or send information in very specific directions or wavelengths, Jacob said.
The researchers plan to design more ceramic materials with polaritonic characteristics for a large number of different applications.
Data Source Provider: Purdue University.