This is a visualization of the different types of diamond-like linkages (red spheres) formed at curved surfaces or between the layers of graphene (black spheres) in this new type of compressed glassy carbon. Images: Timothy Strobel.A team that includes several scientists at the Carnegie Institution for Science has developed a form of ultrastrong, lightweight carbon that is also elastic and electrically conductive. A material with such a unique combination of properties could find use in a wide variety of applications, from aerospace engineering to military armor.
Carbon is an element of seemingly infinite possibilities. This is because the configuration of its electrons allows for numerous self-bonding combinations that give rise to a range of materials with varying properties. For example, both transparent, super-hard diamonds and opaque graphite, which is used in pencils and as an industrial lubricant, are composed solely of carbon.
In this international collaboration between the Carnegie Institution and Yanshan University in China, the scientists pressurized and heated a structurally-disordered form of carbon called glassy carbon. The glassy carbon starting material was brought to about 250,000 times normal atmospheric pressure and heated to approximately 1800°F to create the new strong and elastic carbon. This research is described in a paper in Science Advances.
Scientists had previously tried subjecting glassy carbon to high pressures at both room temperature (referred to as cold compression) and extremely high temperatures. But the so-called cold-synthesized material could not maintain its structure when brought back to ambient pressure, while the extremely hot conditions led to the formation of nanocrystalline diamonds.
The newly-created carbon material is composed of both graphite-like and diamond-like bonding motifs, which gives rise to its unique combination of properties. Under the high-pressure synthesis conditions, disordered layers within the glassy carbon buckle, merge and connect in various ways. This process creates an overall structure that lacks a long-range spatial order, but has a short-range spatial organization on the nanometer scale.
"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 professor at Yanshan University. "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."
This story is adapted from material from the Carnegie Institution for Science, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.