According to the developers, the new material is almost impossible to break, and its scope of application can be different: from photo detectors to protective coatings of cars and coatings of spacecraft.

Diamond is the hardest mineral in nature and also has the highest thermal conductivity of all solid objects. This material is used in microelectronics, photonics, laser technology, ionizing radiation detectors. However, diamonds have a disadvantage. Although its structure is very hard, it is also quite brittle (its strength is not the same in different directions of the crystal). For this reason, diamond’s application areas are limited.

Scientists in laboratories have long been trying to create materials hard enough to handle extreme temperatures, pressures, speeds, voltages and strong radiation.

In 1989, American physicists Marvin Cohen (Marvin Cohen) and Amy Liu (Amy Liu) to synthesize a new superhard material. Scientists have argued that carbon and nitrogen atoms in a 3:4 ratio can form particularly short and strong bonds in stable crystal lattices. According to calculations made by American researchers, the new substance should be as hard as diamond. Remember that nitrides are chemical compounds of nitrogen with metals and nonmetals. with carbon nitride – a binary compound consisting of carbon and nitrogen.

Although Cohen and Liu’s experiments did not meet expectations, they attracted the attention of many scientists. In the future, the existence of various modifications of carbon nitride was predicted. One of these is carbon nitride, which has three-dimensional frameworks of tetrahedra (CN4) – experts called “the best hope of materials science.” Because this material will have a hardness greater than or comparable to the hardness of diamond.

Over the course of three decades, scientists have made a number of attempts to synthesize a new material. But it wasn’t easy. The complexity of the synthesis is mainly due to the thermal instability of carbon nitride (it decomposes at normal temperature of 800 degrees Celsius). A way had to be found to overcome this limitation.

After 30 years, a breakthrough has finally been made in this field. An international research team led by Dominique Laniel (Dominique Lanielfrom the University of Edinburgh (Scotland) said that they managed to synthesize three new carbon nitride compounds: tI14-C3N4, hP126-C3N4 and tI24-CN2.

Based on these compounds, scientists have developed a material that can compete with diamond in terms of hardness. It is harder than boron nitride with a cubic microstructure, which is a synthetic superhard material obtained from the hexagonal modification of boron nitride (BN >) as a result of exposure to high pressures and temperatures. It is the second hardest material after diamond.

Laniel and his colleagues obtained the new compounds by subjecting various forms of carbon nitride precursors to pressures of 70 to 135 gigapascals (one million times greater than atmospheric pressure) and simultaneously heating them to temperatures above 1,500 degrees Celsius.

Then, with the help of X-ray facilities at three particle accelerators (European Synchronous Radiation Center in France), the German Synchrotron DESI and the American Synchrotron Radiation Center – scientists studied the arrangement and atomic structure of atoms in solid crystalline substances.

The analysis showed that the three synthesized carbon nitride compounds (tI14-C3N4, hP126-C3N4, and tI24-CN2) had the suitable structure to form a superhard material. Additional research has revealed that these compounds may have piezoelectric and photoluminescent properties, as well as the ability to store large amounts of energy with a relatively small mass.

“In addition, these compounds retain their superhard properties even after cooling and under normal ambient pressure conditions. As a result of exposure to pressures of over 100 gigapascals, new carbon nitrides are obtained, they can be released into the open air at room temperature [без руйнування]“Laniel explained.

According to the authors, their work will open new opportunities in various areas where diamonds are either unused or used sparingly. In particular, Laniel believes that with the help of the new superhard material created on the basis of three carbon nitride compounds, it will be possible to make photodetectors and sensors, as well as protective coatings for cars and a new type of coating for spacecraft. powerful cutting tools. The results of the study were published in the journal Advanced Materials.