Subjecting carbon and nitrogen to extreme heat and pressure yields the second-hardest material in existence, closely trailing behind diamond.
After decades of pursuit, scientists have successfully synthesized an incredibly hard material, known as carbon nitride, which closely rivals diamond in terms of hardness. This achievement could have significant implications for industries ranging from cutting tools to sensors and explosives.
In 1989, researchers postulated that a material composed of carbon and nitrogen could exhibit exceptional hardness and resistance to shearing, surpassing even the renowned diamond. However, previous attempts to create this elusive substance had proven futile. Now, a team led by Dominique Laniel at the University of Edinburgh, UK, has managed to produce tiny samples of carbon nitride by subjecting carbon and nitrogen to extreme conditions.
To synthesize carbon nitride, researchers employed an ingenious approach involving compressing carbon and nitrogen between diamond points at a staggering 700,000 times atmospheric pressure. Furthermore, they heated the materials to a scorching 3000°C using lasers. The result is a material that boasts a remarkable hardness ranging from 78 to 86 gigapascals (GPa), depending on the specific crystal structure formed. While this falls short of surpassing diamond’s hardness of approximately 90 GPa, it represents a significant step towards closing the substantial gap between diamond and the previous second-hardest material, cubic boron nitride, which scores between 50 and 55 GPa.
Although carbon nitride may not dethrone diamond as the hardest known material, it offers distinct advantages. Despite being more challenging and costly to produce due to the need for intense compression, carbon nitride possesses unique properties. Notably, it generates an electrical signal under pressure, rendering it potentially valuable for sensor applications. Furthermore, its high energy density makes it a candidate for a powerful, environmentally friendly explosive, surpassing current alternatives in terms of ecological impact.
Laniel and his team acknowledge that the material’s name, “carbon nitride,” is somewhat misleading since other materials also consist of these elements but exhibit entirely different characteristics. They remain open to suggestions for a more chemically accurate nomenclature. As they continue their groundbreaking research, the potential applications of carbon nitride could revolutionize various industries, making it a material of great interest to scientists and engineers worldwide.
