Materials

Superfast laser pulses convert carbon nanofibers to diamond at room temperature

Superfast laser pulses convert...
A new technique for converting carbon nanofibers and nanotubes into diamond fibers can be done at room temperature
A new technique for converting carbon nanofibers and nanotubes into diamond fibers can be done at room temperature
View 2 Images
(Left) the carbon nanowire before the pulsed laser annealing (PLA) process turned it into diamond fiber (right)
1/2
(Left) the carbon nanowire before the pulsed laser annealing (PLA) process turned it into diamond fiber (right)
A new technique for converting carbon nanofibers and nanotubes into diamond fibers can be done at room temperature
2/2
A new technique for converting carbon nanofibers and nanotubes into diamond fibers can be done at room temperature

As much mystique as they've been given by companies with vested interest, diamonds are little more than lumps of carbon. In science applications, diamond is useful as a tough protective coating and for optical devices, but its relative rarity on Earth makes it difficult to get. Now, researchers at North Carolina State University have demonstrated a new way to convert carbon nanofibers and nanotubes into diamond fibers that can be performed in a lab more easily than existing techniques.

In nature, diamonds are forged deep in the Earth, where carbon is subjected to high pressure and temperatures, so it makes sense that artificial methods of manufacturing them requires similar conditions. And the equipment involved in that process can be quite cumbersome and energy-intensive.

By contrast, the new technique developed by the NCSU team can apparently be done at room temperature and normal pressure levels. First, carbon nanofibers are hit by a laser pulse lasting just 100 nanoseconds, which instantly heats the carbon to about 3,727° C (6,740° F) and melts it.

(Left) the carbon nanowire before the pulsed laser annealing (PLA) process turned it into diamond fiber (right)
(Left) the carbon nanowire before the pulsed laser annealing (PLA) process turned it into diamond fiber (right)

Normally that heat would be enough to vaporize the carbon, which obviously isn't the desired outcome. To stop that, the team uses a substrate of sapphire, glass or plastic polymer, which restricts the heat flow enough to prevent the phase change. Then the material is quickly cooled, causing it to crystallize into diamond.

This process can create diamond nanofibers for use in electronics and even quantum computers, or to seed carbon nanofibers with tiny diamonds. In the case of the latter, larger diamond structures can then be made using more traditional techniques like chemical vapor deposition. The structures created this way could end up as coatings to toughen up tools or for jewelry.

The research was published in the journal Nanoscale.

Source: North Carolina State University

6 comments
Alien
This is brilliant...and hopefully will enable cheap production of tiny diamonds for industrial use...but I don't think De Beers need worry unduly at this stage. However...there's no telling what might come in the future.
highlandboy
De Beers Have already started to get legal processes in place to have “artificial” diamonds labeled differently to “natural” diamonds. As if there is some quality difference. Unfortunately many people believe the advertising hype about this not so scarce resource. Why people believe this allotrope of carbon is different when dug up instead of created by other processes is baffling.
Sid
@hiboy the answer is simple. Everything natural is always valued more than something that's artificially made. If you had surgery to have your face look handsome would that be as valued?
MerlinGuy
Diamonds are not rare. https://newatlas.com/quadrillion-tons-diamond-cratons/55483/ But the truth is if this process works, is cost effective, and can be scaled up to large sheets then it would be a huge discovery. Sadly, 99.9% of all those discoveries reviewed here never see production.
zr2s10
This isn't really intended for jewelry applications, though I'm sure some will go that way. This is definitely best for industrial use. Optical Diamond is huge right now, and is necessary for modern wafer fabs to make your cell phones and laptops even faster. I don't know that this could really be used for that though, as building on top of fibers with CVD would probably not give the clarity needed.
Nik
This will probably go dormant for a generation or so, and then be ''rediscovered'' and finally put to use, maybe.