Diamond, which boasts high popularity as an ornament, is a hard material and is commonly used as a material for abrasives and drill bits. Although the existence of lonsdaleite, a hexagonal diamond that is harder than such diamonds, was known, a research team at Washington State University succeeded in forming such lonsdaleite.
Hexagonal diamonds are formed when graphite adds strong impact and heat due to meteorite impact. While diamonds usually have a structure called cubic, hexagonal diamonds are in theory harder than cubic diamonds because carbon atoms are arranged in a hexagonal pattern.
However, since natural hexagonal diamonds are found in craters caused by meteorite impacts, hardness measurements with many impurities could not be performed. In addition, research on the formation of hexagonal diamonds in the laboratory has been carried out up to now, but it did not lead to hardness measurement because the formed hexagonal diamonds were too small or the time to exist was too short.
In this study, a 10-cent size, 18mm diameter disk-shaped graphite was collided with the wall at 24,100km/h to reproduce the high energy caused by meteorite impact. As a result, it succeeded in forming a hexagonal diamond with a size sufficient to measure the hardness.
The formed hexagonal diamond collapses in a billionth of a second, but the research team uses a laser to measure the speed of sound wave movement among hexagonal diamonds by using a laser to measure the speed of sound wave movement among the hexagonal diamonds by increasing the speed at which sound waves travel through the material as the material hardens. did.
According to the research team, hexagonal diamonds have higher rigidity than cubic diamonds. In addition, the research team concluded that hexagonal diamonds may be harder than cubic diamonds in the estimated hardness based on stiffness.
The research team appealed for the hardness of hexagonal diamond, saying that diamond provides not only hard crystals, but also beautiful optical properties and high thermal conductivity, and that the hexagonal diamond formed in this study has much higher stiffness and strength than ordinary diamonds.
In addition, he said that hard materials are used in industrial products such as diamond drill bits because of its excellent processing ability. He said that hexagonal diamonds are harder than cubic diamonds and have the potential to be used as an alternative to cubic diamonds for various purposes. have. Related information can be found here.