Q-carbon harder than diamond

Jagdish Narayan, Siddharth Gupta, Anagh Bhaumik, Ritesh Sachan, Filippo Cellini, Elisa Riedo

Research output: Contribution to journalArticle


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.

Original languageEnglish (US)
Pages (from-to)428-436
Number of pages9
JournalMRS Communications
Issue number2
StatePublished - Jun 1 2018

ASJC Scopus subject areas

  • Materials Science(all)

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    Narayan, J., Gupta, S., Bhaumik, A., Sachan, R., Cellini, F., & Riedo, E. (2018). Q-carbon harder than diamond. MRS Communications, 8(2), 428-436. https://doi.org/10.1557/mrc.2018.35