Scientists have turned diamond into graphite for the first time using ultra-short ultraviolet rays of X-rays, a decisive step in understanding the fundamental behavior of solids as they absorb energy radiation. For the first time, researchers including Franz Tavella from the SLAC National Accelerator Laboratory in the US have been able to monitor the time resolution progress of this process.
“In addition to these fundamental aspects, an understanding of graphite generation is important for metallurgical technologies,” said Tavella, first author of the study published in the Journal of High-Density Energy Physics. “Diamonds and graphite are different allotropes of carbon. Diamonds are formed under high pressure from deep within the earth.”
Under normal conditions, diamond is metastable , which means it converts back to graphite when the process is started with enough energy. There are different ways to trigger the diamond-to-graphite conversion, for example by simply heating the diamond under oxygen exclusion or even for impact under chemical catalytic and physical-mechanical conditions, said the researchers.
With high heat and pressure, graphite can be turned into synthetic diamonds.
With high heat and pressure, they say, graphite can be turned into synthetic diamonds, and they’re already on the market worldwide.
The team used an Italian free- flow X-ray laser FERMI machine to shoot ultra-short bursts of small diamond pieces with a thickness of just 0.3mm. “Normally, if you fired powerful laser pulses at ordinary solid objects, it would become amorphous. But diamonds are another example,” the researchers said. It can transform its internal structure to a different order, thus turning into graphite.
“In principle, it is known that if you inject enough energy into a diamond, it will go into an amorphous state,” said Sven Toleikis from the German national research center DESY.
This transition involves a thermal transition , in which absorbed energy is transferred to the crystal lattice within the diamond, which is sufficiently energized until the diamond converts through the graphite structure. .
Another method, the researchers say, is the no-temperature method , in which energy is absorbed by only a fraction of the electrons in the diamond, changing the internal energy surface, causing a rearrangement of the crystal lattice. Beata Ziaja from DESY said. “The non-thermal transition is much faster than the thermal one, which happens in the range of picoseconds, a picosecond is a trillionth of a second.”