Scientists engineer ultra-hard synthetic diamond from graphite
In brief: Chinese researchers have developed a synthetic diamond that is significantly harder and more resilient than those that occur naturally here on Earth. If commercially viable, the new diamond could be a boon for industries that rely on the hardened material.
Most natural and synthetic diamonds feature a cubic lattice structure but there are rare exceptions. Lonsdaleite, for example, is a type of diamond that was first discovered in 1967 in the Canyon Diablo meteorite and boasts a hexagonal lattice structure.
The lab-grown diamond in question is of the hexagonal variety, and was created by heating highly compressed graphite. Using this approach, the team made a millimeter-sized hexagonal diamond that boasts an impressive hardness rating of 155 gigapascals (GPa) and a thermal stability up to 1,100 degrees Celsius. In comparison, most naturally occurring diamonds fall in the 70-100 GPa range with a thermal stability closer to 700 degrees Celsius.
As The Independent highlights, this is not the first time a hexagonal diamond has been explored in the lab. Lawrence Livermore National Laboratory has several papers on the subject dating back years, but understanding of the subject has been hampered by small sample sizes and low purity levels.
Professor Oliver Williams, chair of the condensed matter and photonics group at Cardiff University, told Metro that despite the new diamond’s rarity, it would be no more expensive than natural ones sold at jewelry stores. For it to be a commercial success, however, the price would have to be significantly lower than natural diamonds.
Obvious use cases would include industrial applications like drilling or machining, where long-lasting tools are a must. It is also not outside the realm of possibility that hexagonal diamonds could one day be used for thermal management, advanced data storage, or even as a replacement for silicon in tech applications – assuming, of course, that the hexagonal lattice affords an advantage over traditional cubic structures.
The team’s research has been published in the journal Natural Materials.
Image credit: Stock Cake, Dillon Wanner
