Successfully manufactured super light insulation material
Scientists have successfully created a new type of insulator that is nearly weightless and has higher thermal stability than most other materials.
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Experiments show the new material's very high thermal insulation properties. Photo: X. Xu Et Al/Science 2019. |
The new material is an aerogel structure (at least 99 percent empty space), made from an atomically thin ceramic (hexagonal boron nitride). This design demonstrates extremely high thermal stability and rapid temperature changes over a range of more than 1,000 degrees Celsius, scientists report in the February 15 issue of the journal Science.
“It’s very difficult to create materials that are both lightweight and heat-resistant,” said Deep Jariwala, an engineer at the University of Pennsylvania who co-authored a commentary on the study in the journal Science. The new ultralight insulator has potential as a coating on spacecraft components, which must endure extreme temperature changes as they fly toward the sun or re-enter Earth’s atmosphere, he said.
The aerogel’s structure consists of a network of tiny air bubbles, each separated by two layers of hexagonal boron nitride (a trivalent metalloid element). Just as double-pane windows prevent heat from escaping a house in the winter, this double-pane ceramic barrier makes it difficult for heat to transfer from one air bubble to another. “It’s very difficult for heat to travel through the material along the boron nitride layers, because of the long and winding path,” says Xiangfeng Duan, a chemist and materials scientist at the University of California, Los Angeles.
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| Experiments show the new material's very high thermal insulation properties. Photo: X. Xu Et Al/Science 2019. |
The researchers placed a fresh flower on a 2-centimeter-thick piece of the new material and placed it under a flame (the heat map on the right shows). After 15 minutes, the top surface measured 45 degrees Celsius and the flower had only slightly wilted.
While other aerogels can break under rapid temperature changes or under prolonged exposure to heat, the new aerogel material can withstand up to 500 rapid heating and cooling cycles from 198 degrees to 900 degrees Celsius (increasing or decreasing by 275 degrees per second), and is also stable (retaining 95% of its flexibility) at 1400 degrees Celsius for a week.
The new material is still soft and flexible, so for practical applications it would probably need to be encased in another, more durable material, says Julia Greer, a materials scientist at the California Institute of Technology.
