Scientists have developed a form of ultrastrong, lightweight carbon that is hard as a diamond yet elastic like rubber and electrically conductive.
"In simple terms, the material combines the best properties of graphitic- and diamond-like forms of carbon," study co-lead author Zhisheng Zhao, professor at Yanshan University, China, said in an email to Xinhua.
"This combination of properties is useful for many potential applications, such as military armor and aerospace."
The findings were published this week by the U.S. journal Science Advances.
Carbon is an element of seemingly infinite possibilities. This is because it has the flexibility to form different types of chemical bonds, which allows it to exhibit a variety of fascinating structures.
According to Zhao, pressure is an effective tool to control this chemical bonding and induce so-called phase transformations.
For example, under high-pressure conditions, soft graphite transforms into diamond, the hardest material known.
In the new study, scientists pressurized and heated a structurally disordered form of carbon called glassy carbon to create the new form of carbon.
"The process is similar to converting graphite into diamond, however, in our new approach, the temperature used is not high enough to produce diamond," Zhao said.
"The resulting compressed glassy carbon exhibits exceptional hybrid properties in that it is lightweight, ultrastrong, very hard, elastic and electrically conductive."
Specifically, the compressed glassy carbon is more than two times stronger than commonly used carbon fibers, cemented diamond, silicon carbide and boron carbide ceramics.
It also has high hardness compared with commonly used ceramics, is electrically conducting and simultaneously exhibits a robust elastic recovery that's higher than shape-memory alloys and organic rubber.
"Our future work will continue to develop this methodology and create new structural materials with high strength, hardness and elasticity," said Zhao. "Our ultimate goal is to obtain the extremely strong and superhard materials with superelasticity."
The findings also included researchers from Carnegie Institution of Washington, and Shanghai-based Center for High Pressure Science and Technology Advanced Research, the University of Chicago and the Pennsylvania State University.
