New form of carbon is tough and elastic

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A joint US-China research team has discovered a new form of carbon that is ultra strong, yet elastic like rubber.   

(Credit: Timothy Strobel)

Developed by engineers at Washington DC’s Carnegie Institute for Science and China’s Yanshan University, the material is also lightweight and electrically conductive. The researchers claim it could have a wide array of applications, ranging from aerospace engineering to military armour.

To create it, the team pressurised and heated a structurally disordered form of carbon called glassy carbon. This starting material was brought to about 250,000 times normal atmospheric pressure and heated to around 1,000 degrees Celsius. Under the high-pressure synthesis conditions, disordered layers within the glassy carbon buckle, merge, and connect in various ways, resulting in a form of carbon that exhibits traits of both diamond and graphite, two of carbon’s allotropes. The findings are published in the journal Science Advances.   

"Light materials with high strength and robust elasticity like this are very desirable for applications where weight savings are of the utmost importance, even more than material cost," explained Zhisheng Zhao a former Carnegie fellow, who is now a Yanshan University professor.

"What's more, we believe that this synthesis method could be honed to create other extraordinary forms of carbon and entirely different classes of materials."

According to the team, the new material has a compressive strength more than two times that of commonly used ceramics, while simultaneously exhibiting robust elastic recovery in response to local deformations. Scientists had previously subjected glassy carbon to high pressures at both room temperature (known as cold compression) and extremely high temperatures, but the former could not maintain its structure when brought back to ambient pressure, while the latter resulted in the formation of nanocrystalline diamonds. Using a relatively more moderate temperature for their synthesis method, the team was able to create a stable material with a host of desirable attributes.