Scientists have discovered a fascinating and complex tiny structure that had never been seen before when examining diamonds inside an old meteorite.
The structure, which is an interlocking form of graphite and diamond, has special qualities that could one day be used to create faster charging or new types of electronics, the researchers say.
The “Diablo Canyon” meteorite, as it is known, hit the Earth around 50,000 years ago and was first discovered in Arizona in 1891. This meteorite is composed of ~90% you should~1-4% yesand up to 8.5% trollite– graphite nodules (FeS & C). The original mass was estimated to be 100 feet in diameter and about 60,000 tons.
It is believed that the strange diamond structures formed and were encased in the meteorite during this event.
This meteorite contains diamonds, but not the common varieties. Most diamonds form nearly 90 miles (150 kilometers) below the Earth’s surface, where temperatures can reach over 2,000 degrees Fahrenheit (1,093 degrees Celsius). The temperature and pressure at this depth cause the carbon atoms to arrange themselves into cubic shapes.
In contrast, the diamonds found inside the “Canyon Diablo” meteorite have a hexagonal crystal structure and are known as lonsdaleite (named after British crystallographer Dame Kathleen Lonsdale, the first female professor at University College London). These types of crystals, it was discovered, can only form at incredibly high pressures and temperatures.
Scientists have replicated similar structures, but they are usually only found in meteorites
Scientists have succeeded in making lonsdaleite in a laboratory – using gunpowder and compressed air to propel discs of graphite at 15,000 mph (24,100 km/h) against a wall – lonsdaleite usually forms only when asteroids hit Earth at extremely high speeds.
Regarding the diamonds of the “Diablo Canyon” meteorite, scientists noticed an unusual phenomenon when analyzing the lonsdaleite in the meteorite. For example, they discovered growths of another carbon-based substance called graphene interacting with diamond instead of the pure hexagonal formations they had anticipated.
These growths, called diaphites, take on the appearance of a particularly fascinating layered pattern inside the meteorite. “Stack faults” between these layers indicate that the layers do not align precisely, according to the researchers’ statement.
The discovery of diaphites in meteorite lonsdaleite raises the possibility that this resource is widely accessible because it can be found in other carbonaceous materials, according to the researchers’ findings. The discovery also improves researchers’ understanding of the temperatures and pressures needed to build the structure.
Graphene is made of a sheet of carbon one atom thick, arranged in hexagons. The material has many potential applications, although research into it is still in its infancy.
It could one day be used for more precise medical treatments, smaller electronic devices with super-fast charging speeds, or faster, more flexible technology, the researchers said, because it’s both as light as it is a feather and as strong as a diamond, transparent and highly conductive and 1 million times thinner than a human hair.
Since these graphene growths have been found inside meteorites, researchers can now learn more about their appearance and, therefore, how to create them in the lab.
“Through the controlled growth of the layers of the structures, it should be possible to design materials that are both ultra-hard and ductile, as well as tunable electronic properties from conductor to insulator,” said Christoph Salzmann, chemist at University College London. and co-author of an article describing the research, said in the press release.
The strange new structures were described on July 22, 2022 in the newspaper Proceedings of the National Academy of Sciences.
Summary of the study:
“Studies of dense carbonaceous materials formed by bolide impacts or produced by compression in the laboratory provide key information on the high pressure behavior of carbon and for identifying and designing unique structures for technological applications. he study and design of these materials is an incomplete understanding of their fundamental structures. Here, we report the remarkable structural diversity of cubic/hexagonal (vs/h) stacked diamond and their association with sp-containing diamond-graphite nanocomposites3-/sp2– bonding patterns, i.e. diaphites, from hard carbonaceous materials formed by the shock impact of graphite in the iron meteorite Canyon Diablo. We show evidence for a range of intergrowth types and nanostructures containing unusually short (0.31 nm) graphene spacings and demonstrate that previously overlooked or misinterpreted Raman bands may be associated with diaphite structures. Our study provides a structural understanding of the material known as lonsdaleite, previously described as a hexagonal diamond, and extends this understanding to other natural and synthetic ultrahard carbon phases. The unique three-dimensional carbon architectures encountered in impact-formed samples can impose constraints on the pressure-temperature conditions encountered during impact and provide unique opportunities to engineer the properties of carbon nanocomposite materials and phase assemblies.