DIAMOND鈥檚 crown has well and truly slipped. The 鈥渨orld鈥檚 hardest material鈥� arguably lost its title a while ago to tough nanomaterials. Now a substance sometimes found in nature may beat them all 鈥� at 58 per cent harder than diamond.
Zicheng Pan at Shanghai Jiao Tong University in China and colleagues simulated how atoms in two materials respond when a fine-tipped probe pushes at them. The first, wurtzite boron nitride, is similar in structure to diamond but made of boron and nitrogen. The second, lonsdaleite, is made from carbon atoms like diamond but they are arranged differently. The simulation showed that WBN would withstand 18 per cent more stress than diamond and lonsdaleite, 58 per cent more 鈥� a potential new record ().
Both are rare in nature, so the next step is to make enough in the lab to test the prediction. If confirmed, WBN may be the most useful. Because it is stable in oxygen at higher temperatures than diamond, it could be used for the tips of drilling tools, which work at blazing temperatures, or in corrosion-resistant films on the surface of spacecraft.
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