Scientists create new form of carbon harder than diamond

[Borgholio]

https://news.ncsu.edu/2015/11/narayan-q-carbon-2015/

Researchers from North Carolina State University have discovered a new phase of solid carbon, called Q-carbon, which is distinct from the known phases of graphite and diamond. They have also developed a technique for using Q-carbon to make diamond-related structures at room temperature and at ambient atmospheric pressure in air.

Phases are distinct forms of the same material. Graphite is one of the solid phases of carbon; diamond is another.

“We’ve now created a third solid phase of carbon,” says 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.”

Q-carbon has some unusual characteristics. For one thing, it is ferromagnetic – which other solid forms of carbon are not.

“We didn’t even think that was possible,” Narayan says.

In addition, Q-carbon is harder than diamond, and glows when exposed to even low levels of energy.

“Q-carbon’s strength and low work-function – its willingness to release electrons – make it very promising for developing new electronic display technologies,” Narayan says.

But Q-carbon can also be used to create a variety of single-crystal diamond objects. To understand that, you have to understand the process for creating Q-carbon.

Researchers start with a substrate, such as such as sapphire, glass or a plastic polymer. The substrate is then coated with amorphous carbon – elemental carbon that, unlike graphite or diamond, 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 4,000 Kelvin (or around 3,727 degrees Celsius) and then rapidly cooled. This operation takes place at one atmosphere – the same pressure as the surrounding air.

The end result is a film of Q-carbon, and researchers can control the process to make films 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. By changing the rate of cooling, they are able to create diamond structures within the Q-carbon.

“We can create diamond nanoneedles or microneedles, nanodots, or large-area diamond films, with applications for drug delivery, industrial processes and for creating high-temperature switches and power electronics,” Narayan says. “These diamond objects have a single-crystalline structure, making them stronger than polycrystalline materials. And it is all done at room temperature and at ambient atmosphere – 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.”

And, if researchers want to convert more of the Q-carbon to diamond, they can simply repeat the laser-pulse/cooling process.

If Q-carbon is harder than diamond, why would someone want to make diamond nanodots instead of Q-carbon ones? Because we still have a lot to learn about this new material.

“We can make Q-carbon films, and we’re learning its properties, but we are still in the early stages of understanding how to manipulate it,” Narayan says. “We know a lot about diamond, so we can make diamond nanodots. We don’t yet know how to make Q-carbon nanodots or microneedles. That’s something we’re working on.”

NC State has filed two provisional patents on the Q-carbon and diamond creation techniques.

The work is described in two papers, both of which were co-authored by NC State Ph.D. student Anagh Bhaumik. “Novel Phase of Carbon, Ferromagnetism and Conversion into Diamond” was published online Dec. 2 in the Journal of Applied Physics. “Direct conversion of amorphous carbon into diamond at ambient pressures and temperatures in air” was published Oct. 7 in the journal APL Materials. The work was supported in part by the National Science Foundation, under grant number DMR-1304607.

[Iroscato]

That's really cool

Particularly the part about it being magnetic.

[jwl]

Who cares about it being harder than diamond when you have a ferromagnetic carbon allotrope? I concur with Narayan: I didn't think that was even possible, either.

Although are they sure it's ferromagnetic and not ferrimagnetic? It's hard to tell from the hysteresis loop.

[Iroscato]

Who cares about it being harder than diamond when you have a ferromagnetic carbon allotrope? I concur with Narayan: I didn't think that was even possible, either.

Although are they sure it's ferromagnetic and not ferrimagnetic? It's hard to tell from the hysteresis loop.

...

It's slightly annoying how often this forum makes me have to google words

[Jaepheth]

Who cares about it being harder than diamond when you have a ferromagnetic carbon allotrope? I concur with Narayan: I didn't think that was even possible, either.

Although are they sure it's ferromagnetic and not ferrimagnetic? It's hard to tell from the hysteresis loop.

From the abstract:

It is expected to have new and improved mechanical hardness, electrical conductivity, chemical, and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission.

Sounds really promising. I especially like that it doesn't take extreme environments or super-specialized equipment to manufacture.

[Broomstick]

That's a very interesting development. And it being relatively low-cost is exciting.

[Elheru Aran]

From the abstract:

It is expected to have new and improved mechanical hardness, electrical conductivity, chemical, and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission.

Sounds really promising. I especially like that it doesn't take extreme environments or super-specialized equipment to manufacture.

Because people tend to just have amorphous carbon and fancy lasers sitting around that they can dial in 200-nanosecond bursts

[Iroscato]

From the abstract:

It is expected to have new and improved mechanical hardness, electrical conductivity, chemical, and physical properties, including room-temperature ferromagnetism (RTFM) and enhanced field emission.

Sounds really promising. I especially like that it doesn't take extreme environments or super-specialized equipment to manufacture.

Because people tend to just have amorphous carbon and fancy lasers sitting around that they can dial in 200-nanosecond bursts

You mean you don't? Peasant.

[Broomstick]

The average kitchen has several forms of carbon of varying purity. As just one example.

[biostem]

Is it conductive? If they can create thin layers of it on demand, and it is conductive, it could eliminate having to use the fairly toxic doping process required to get the little pathways on circuit boards... just have a laser on some CNC rig trace out the desired path on the main board.

[SpottedKitty]

It's stable in normal room temperature conditions after being created? Weird, and fascinating.

[Zeropoint]

The universe is not only stranger than we imagine, it is stranger than we can imagine.

This stuff is super cool, and I hope to see many amazing technologies come of it.

[Reaver225]

This stuff is super cool

I hope not, room temperature is much more useful!

Given the cheapness of the raw material and potential effectiveness of industrial lasers, might we hope for the cheap extruded diamond structures ala Neal Stephenson's The Diamond Age? Or would that seem like a bad idea due to the materials involved, timeframes, or energy costs of running the lasers, compared to traditional building materials and labour?

What about uses in 3D printing? The stuff coming in films seems to suggest it could be used for that. Any other potential applications?

[Starglider]

Given the cheapness of the raw material and potential effectiveness of industrial lasers, might we hope for the cheap extruded diamond structures ala Neal Stephenson's The Diamond Age? Or would that seem like a bad idea due to the materials involved, timeframes, or energy costs of running the lasers, compared to traditional building materials and labour?

Laser flash phase change processes are not really suitable for bulk structures, as they only produce tiny crystals or films (micrometre thickness or less). Even if you're stacking films, bonding between them will be dubious and you will likely get lots of inclusions and cause damage to the previous film growing the next one. 'Diamond Age' style nanotechnology is based on physical assembly of crystals using structures roughly equivalent to mechanical, digitally controlled enzymes (not tiny robotic arms as many early boosters portrayed it!). This looks like it should work in the sense that we can simulate some of the structures and they don't break any laws of physics, but we can't actually make them yet. That kind of dry fully-controlled nanoassembly is still a fair way off although steady progress is being made.

What about uses in 3D printing? The stuff coming in films seems to suggest it could be used for that. Any other potential applications?

Expensive very-difficult-to-make materials with exotic properties tend to be used first in specialist applications that can justify the extreme cost per kilo, R&D and/or exotic plant and tooling required, not general industrial or mass market use. I think they're still at the stage of quantifying the properties and working out what a pilot production plant would even look like, so speculation on near-term applications is a bit premature.

[Enigma]

But is it 400x stronger than diamond?