Researchers used a multi-anvil press to turn fullerene C60 into diamond glass, similar to the way graphite can be converted into diamond in high-pressure apparatus. Image: Yingwei Fei.An international research team has synthesized a new ultrahard form of carbon glass with a wealth of potential practical applications for devices and electronics. It is the hardest known glass with the highest thermal conductivity amongst all glass materials. The team, which includes researchers from the Carnegie Institution of Science, reports its work in a paper in Nature.
Function follows form when it comes to understanding the properties of a material. How its atoms are chemically bonded to each other, and their resulting structural arrangement, determines a material’s physical qualities – both those that are observable by the naked eye and those that are only revealed by scientific probing.
Carbon is unrivaled in its ability to form stable structures – alone and in combination with other elements. Some forms of carbon are highly organized, with repeating crystalline lattices. Others are more disordered, a quality termed amorphous.
The type of bond holding a carbon-based material together determine its hardness. For example, soft graphite has two-dimensional bonds and hard diamond has three-dimensional bonds.
“The synthesis of an amorphous carbon material with three-dimensional bonds has been a long-standing goal,” explained Yingwei Fei from the Carnegie Institution. “The trick is to find the right starting material to transform with the application of pressure.”
“For decades Carnegie researchers have been at the forefront of the field, using laboratory techniques to generate extreme pressures to produce novel materials or mimic the conditions found deep inside planets,” added Richard Carlson, director of the Carnegie Earth and Planets Laboratory.
Because of its extremely high melting point, diamond can't be used as the starting point for synthesizing diamond-like glass. However, the research team, led by Bingbing Liu and Mingguang Yao – a former Carnegie visiting scholar – at Jilin University in China, made their breakthrough by using a form of carbon composed of 60 molecules arranged to form a hollow ball. Informally called a buckyball, this Nobel Prize-winning material was heated just enough to induce disorder by collapsing its soccer-ball-like structure, before applying pressure to turn the carbon into crystalline diamond.
The team used a large-volume multi-anvil press to synthesize the diamond-like glass, which was sufficiently large for characterization. The researchers confirmed it properties using a variety of advanced, high-resolution techniques for probing atomic structure.
“The creation of a glass with such superior properties will open the door to new applications,” Fei explained. “The use of new glass materials hinges on making large pieces, which has posed a challenge in the past. The comparatively lower temperature at which we were able to synthesize this new ultrahard diamond glass makes mass production more practical.”
This story is adapted from material from the Carnegie Institution of 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.