Successful development of materials as hard as diamond

Diamond remains the hardest known material in the world . It has found its way into the tools of choice for the toughest tasks, from saw blades to spacecraft parts.

Since the late 1980s, scientists have been looking for ways to replace diamond mining, which is often associated with exploitative labor and environmental damage, with a material called carbon nitride.

New material from carbon nitride has hardness close to diamond, has potential application in many different fields

Carbon nitride, made from carbon and nitrogen, could theoretically rival the hardness of diamond, but an industrial-scale solution is unlikely in the long term.

Three decades later, an international team of scientists from the University of Edinburgh, the University of Bayreuth and Linköping University has finally achieved a major breakthrough in producing this superhard material. Essentially, the scientists had to recreate the natural conditions of the elements that exist at the center of the Earth.

To do this, scientists compressed carbon and nitrogen to 700,000 times atmospheric pressure. They also used lasers to heat the material to 2,732 degrees Fahrenheit (1,500 degrees Celsius). Next, they exposed the samples to high-intensity X-ray beams at three particle accelerators (located in France, Germany, and the United States).

The research was published in October 2023 in the journal Advanced Materials. Scientists discovered three carbon nitride compounds with extremely high hardness and retained diamond-like properties when returned to ambient temperature and pressure conditions.

“With the discovery of new carbon nitride materials, we are starting to think about creating materials that researchers have dreamed of for three decades,” said Dominique Laniel, a co-author of the study from the University of Edinburgh. “These materials bring high-pressure synthesis and industrial applications closer together.”

Further research also showed that the new material contains additional properties such as the ability to emit light and store high energy density in a small volume.

Carbon nitride is not a complete replacement for natural diamonds. A diamond has a hardness of about 90 gigapascals (GPa), while a block of boron nitride has a hardness of only about 50 to 55 GPa. The new carbon nitride compounds have a hardness of between 78 and 86 GPa, depending on the crystal structure. The difference in numbers is not much, but it is not enough to overtake diamond as the number one material.

The new material the scientists created is just 5x3 micrometers in size. And to create larger samples would require larger diamonds and even greater pressure, making the new superhard carbon nitride extremely expensive.

However, cost-cutting will be the goal as the material has an advantage over conventional diamonds in that it can generate electrical signals - a handy feature when used in sensors.

The Viet (Source: PopMech)

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