Researchers at Carnegie Science have developed a super hard diamond glass. This new material is made entirely of crushed "football" carbon and also has high thermal conductivity and can be used in electronic products.

Carbon is a multifunctional element that forms many stable structures in various atomic arrangements from graphene to diamond. They can be repeating crystalline patterns or amorphous like glass. The atomic bonds themselves can be formed in two or three dimensions, which determines the hardness of the material. However, some forms, such as diamond glass, are more difficult to make than others.

"Synthesizing amorphous carbon materials with three-dimensional bonds has always been a long-term goal," said Fei Yingwei, author of the new study. "The trick is to find the right starting material and apply pressure to transform it."

For example, if pressure is applied to graphite, the crystal arrangement of diamond will eventually be obtained. Diamond itself seems to be a logical starting point for the manufacture of diamond glass, but its melting point of 4,227 °C (7,640 °F) is too high for practical use. The team needed to find a form of carbon that could become sufficiently disordered atomically before being stressed.

They found their goal in fullerenes. It is widely known as a bucky ball. It consists of 60 carbon atoms arranged in a hollow football shape. The team heated them until the ball shape collapsed into a disorderly arrangement, and then applied high pressure using a multi-anvil press. The end result is a diamond-like glass that can be produced into millimeter-sized fragments.

After careful inspection, the team found that the hardness of the new glass was about 102 gigapascals (GPa). This is higher than natural diamonds, but not as hard as AM-III, which is a recently synthesized glass in China with a hardness of 113 GPa.

The team also claimed that the thermal conductivity of this new type of super-hard glass is the highest among all amorphous materials, with a k value of 26. Importantly, it can be synthesized at a temperature of 900 to 1,000 °C (1,652 to 1,832 °F), which means that industrial manufacturing is within reach.

"Making glass with such excellent performance will open the door to new applications," Fei said. "The use of new glass materials depends on the manufacture of large pieces, which posed a challenge in the past. We were able to synthesize this new type of superhard diamond glass at a relatively low temperature, which makes mass production more practical."

The research was published in the journal Nature.