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Q-carbon harder than diamond

  • Jagdish Narayan (a1), Siddharth Gupta (a1), Anagh Bhaumik (a1), Ritesh Sachan (a1) (a2), Filippo Cellini (a3) (a4) and Elisa Riedo (a3) (a4) (a5)...

A new phase of carbon named Q-carbon is found to be over 40% harder than diamond. This phase is formed by nanosecond laser melting of amorphous carbon and rapid quenching from the super-undercooled state. Closely packed atoms in molten metallic carbon are quenched into Q-carbon with 80–85% sp3 and the rest sp2. The number density of atoms in Q-carbon can vary from 40% to 60% higher than diamond cubic lattice, as the tetrahedra packing efficiency increases from 70% to 80%. Using this semiempirical approach, the corresponding increase in Q-carbon hardness is estimated to vary from 48% to 70% compared to diamond.

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MRS Communications
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