RAPAPORT... Researchers at North Carolina State University (NC State) have
discovered a method of producing diamond at room temperature and ambient
atmospheric pressure in air, identifying a third and previously unknown form of
carbon.
While the two known ‘phases’ of solid carbon – distinct
forms of the same material – are graphite and diamond, the experts said they
have created another phase. Known as Q-carbon, it is ferromagnetic, harder than
diamond and glows in the dark, the university said in a statement.
Researchers have developed a technique for using Q-carbon to
make diamond-related structures. The substance could
be used to create a “variety of single-crystal diamond objects,” the statement said
November 30.
“We’ve now created a third solid phase of carbon,” according
to Jay Narayan, the John C. Fan distinguished chair professor of materials science
and engineering at NC State and lead author of three papers describing the
work. “The only place it may be found in the natural world would be possibly in
the core of some planets.”
The creation process starts with a substrate such as
sapphire, glass or a plastic polymer. The substrate is then coated with amorphous
carbon which does not have a regular, well-defined crystalline structure.
The carbon is then hit with a single laser pulse lasting
approximately 200 nanoseconds. During this pulse, the temperature of the carbon
is raised to around 3,727 degrees Celsius and then rapidly cooled. The process takes
place in the same pressure as the surrounding air and leaves a film of
Q-carbon, which can be controlled to be between 20 nanometers and 500
nanometers thick.
By using different substrates and changing the duration of
the laser pulse, the researchers can also control how quickly the carbon cools,
the university said. By changing the rate of cooling, they are able to create
diamond structures within the Q-carbon.
“These diamond objects have a single-crystalline structure,
making them stronger than polycrystalline materials,” Narayan said. “We’re
basically using a laser like the ones used for laser eye surgery. So, not only
does this allow us to develop new applications, but the process itself is
relatively inexpensive.”
One of the new substance’s additional benefits could be for
new electronic display technologies, he added. NC State has filed two
provisional patents for the Q-carbon and diamond-creation techniques, the statement
said.
The work, by Narayan and NC
State PhD student Anagh Bhaumik, was published October 7 in the journal APL Materials, while a
second article was slated to be published in the Journal of
Applied Physics November 30.
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