Materials: Scientists create ‘ultra-hard’ GLASS that is even harder than a diamond

It may soon be time to ditch that bulky phone case, as scientists have created an ultra-hard glass that’s even harder than natural diamonds.

The so-called carbon glass, which also has the highest thermal conductivity of all known glasses, was produced by researchers led by China’s Jilin University.

They synthesized it by placing “buckyballs” — a football-like form of carbon — into an anvil press and subjecting them to extreme temperatures and pressures.

For example, the sample pictured below was formed at 30 GPa and 1598°F, although production was possible at lower pressures and higher temperatures and vice versa.

The hardness achieved – about 102 GPa – makes it one of the hardest glasses currently known, second only to the recently synthesized AM-III carbon (113 GPa).

It may soon be time to ditch that bulky phone case, as scientists have created an ultra-hard glass that's even harder than natural diamonds.  Pictured: A sample of the carbon glass, about 1 millimeter wide, which was formed at 30 GPa and 1,598 °F (870 °C)

It may soon be time to ditch that bulky phone case, as scientists have created an ultra-hard glass that’s even harder than natural diamonds. Pictured: A sample of the carbon glass, about 1 millimeter wide, which was formed at 30 GPa and 1,598 °F (870 °C)

The so-called carbon glass, which also has the highest thermal conductivity of all known glasses, was produced by researchers led by China's Jilin University.  Pictured: Ever-magnified transmission electron microscope images of the new carbon glass

The so-called carbon glass, which also has the highest thermal conductivity of all known glasses, was produced by researchers led by China's Jilin University.  Pictured: Ever-magnified transmission electron microscope images of the new carbon glass

The so-called carbon glass, which also has the highest thermal conductivity of all known glasses, was produced by researchers led by China’s Jilin University. Pictured: Ever-magnified transmission electron microscope images of the new carbon glass

What is ultra-hard glass?

A team of Chinese scientists led by Yanshan University recently unveiled a transparent, yellow-tinted glass called AM-III, which can leave a deep scratch on a diamond.

Made entirely of carbon, the material reached 113 gigapascals (GPa) on the Vickers hardness test, while diamonds typically score somewhere between 50 and 70 on the GPa scale.

In comparison, Dr. Fei and colleagues scored just 102 GPa in the test.

AM-III is not a diamond replacement, according to the researchers, but could be used to develop stronger solar cells in solar panels and tougher bulletproof windows that would be 20 to 100 percent stronger than current models.

“Creating a glass with such superior properties will open the door to new applications,” said author and geochemist Yingwei Fei of the Carnegie Institution for Science in Washington.

‘Using new glass materials relies on making large pieces, which has been a challenge in the past.

‘The relatively low temperature at which we were able to synthesize this new ultra-hard diamond glass makes mass production more practical.’

Carbon can take several stable forms, which differ based on their molecular structure. Some — like graphite and diamond — are highly textured, while others are disordered or “amorphous,” like regular glass.

The hardness of any shape is determined by the internal bonds. Graphite, for example, is flaky because it has a two-dimensional arrangement of bonds, with layers of highly bonded carbon atoms in a flat, hexagonal pattern.

Diamond, meanwhile, has a three-dimensional arrangement of bonds, giving it a more uniform hardness.

‘The synthesis of an amorphous carbon material with three-dimensional bonds is a long-standing goal,’ explains Dr Fei.

‘The trick is to find the right starting material under pressure to transform.’

Due to its extremely high melting point of a staggering 7,280°F (4,027°C), it is impossible to use diamond as a starting point to create diamond-like glass.

Instead, the team turned to buckminsterfullerene, a form of carbon composed of 60 atoms arranged in a hollow, cage-like structure that resembles a football, a fact that has given it the popular name “buckyball.”

The discovery of buckyballs was awarded the Nobel Prize in Chemistry in 1996.

Due to its extremely high melting point of a staggering 7,280°F (4,027°C), it is impossible to use diamond as a starting point to create diamond-like glass. Instead, the team turned to buckminsterfullerene, a form of carbon made up of 60 atoms arranged in a hollow structure that resembles a football, a fact that has given it the popular name “buckyball.”

To make a diamond-like carbon glass from buckminsterfullerene, the researchers compressed and heated buckyballs in a so-called high-volume multi-anvil press.

This process caused the ball-like molecules to collapse, causing local disorder while preserving a diamond-like order at close to medium range. Although the resulting glasses were small, about 1 mm in diameter, they were large enough for characterization.

These discoveries contribute to our understanding of advanced amorphous materials and the synthesis of bulk amorphous materials using high-pressure and high-temperature techniques,” the team concluded.

The findings, they added, “could open up new uses for amorphous solids.”

‘For decades [our] researchers are at the forefront of the field, using laboratory techniques to generate extreme pressures to produce new materials,” said Richard Carlson, director of the Carnegie Earth and Planets Laboratory.

The study’s full findings were published in the journal Nature.

HOW DO SCIENCE ‘GROW’ DIAMONDS IN A LAB?

Diamonds get their high price tag because they form over millions of years under high pressure and temperatures deep within the Earth’s crust.

But a number of companies are now growing the gemstones in labs around the world, threatening to shake up the diamond industry.

A small ‘seed’ diamond acts as a scaffold for the process.

Scientists first place this seed in a vacuum chamber to remove impurities from the air.

Lab-created gems threaten to upset the diamond industry as several companies around the world grow the stones for jewelry.  In this image Lisa Bissell, CEO of Pure Grown Diamonds, unveils a lab-grown diamond in New York in 2015.

Lab-created gems threaten to upset the diamond industry as several companies around the world grow the stones for jewelry.  In this image Lisa Bissell, CEO of Pure Grown Diamonds, unveils a lab-grown diamond in New York in 2015.

Lab-created gems threaten to upset the diamond industry as several companies around the world grow the stones for jewelry. In this image Lisa Bissell, CEO of Pure Grown Diamonds, unveils a lab-grown diamond in New York in 2015.

They then direct hydrogen and methane gas up to 3,000°C (5,400°F) into the chamber to create a highly charged gas known as plasma.

The gases quickly decompose, releasing carbon atoms from the methane that accumulated on the diamond ‘seed’.

These atoms naturally copy the crystal structure of organic diamond, which is also made up of carbon atoms.

Each artificial stone grows at a rate of approximately 0.0002 inches (0.006 mm) per hour.

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