The new diamond: Researchers create ‘near unbreakable substance’ to rival coveted precious stone

Scientists have created an unbreakable substance that could rival diamond as the hardest material on Earth. The researchers found that when carbon and nitrogen precursors are subjected to extreme heat and pressure, the resulting materials called carbon nitrides tend to be tougher than cubic boron nitride - the second hardest material after diamond.

But the new breakthrough can be used for new multifunctional materials for industrial uses including protective coatings for cars and spaceships, high-endurance cutting tools, solar panels and photodetectors, according to the new study, published in the journal Advanced Materials. In the latest study, after decades of investigation, researchers, including those from the University of Edinburgh, subjected various forms of carbon-nitrogen precursors to pressures between 70 and 135 gigapascals which is around 1 million times our atmospheric pressure - while heating them to temperatures of over 1,500C.

They then analysed the atomic arrangement of the resulting compounds under the same conditions and found three carbon nitride compounds have the necessary building blocks for super-hardness. The compounds also retained their diamond-like qualities when they returned to ambient pressure and temperature conditions, and these three substances had high energy density with a large amount of energy concentrated in a small amount of mass - and this can rival diamonds.

Study co-author Dominique Laniel said: "These materials provide a strong incentive to bridge the gap between high-pressure materials synthesis and industrial applications. These materials are not only outstanding in their multi-functionality, but show that technologically relevant phases can be recovered from a synthesis pressure equivalent to the conditions found thousands of kilometres in the Earth’s interior."