Giant Increase of Hardness in Silicon Carbide by Metastable Single Layer Diamond-Like Coating

Martin Rejhon, Xinliu Zhou, Francesco Lavini, Alessandra Zanut, Filip Popovich, Lorenzo Schellack, Lukasz Witek, Paulo Coelho, Jan Kunc, Elisa Riedo

Research output: Contribution to journalArticlepeer-review

Abstract

Silicon carbide (SiC) is one of the hardest known materials. Its exceptional mechanical properties combined with its high thermal conductivity make it a very attractive material for a variety of technological applications. Recently, it is discovered that two-layer epitaxial graphene films on SiC can undergo a pressure activated phase transition into a sp3 diamene structure at room temperature. Here, it is shown that epitaxial graphene films grown on SiC can increase the hardness of SiC up to 100% at low loads (up to 900 µN), and up to 30% at high loads (10 mN). By using a Berkovich diamond indenter and nanoindentation experiments, it is demonstrated that the 30% increase in hardness is present even for indentations depths of 175 nm, almost three hundred times larger than the graphene film thickness. The experiments also show that the yield point of SiC increases up to 77% when the SiC surface is coated with epitaxial graphene. These improved mechanical properties are explained with the formation of diamene under the indenter's pressure.

Original languageEnglish (US)
JournalAdvanced Science
DOIs
StateAccepted/In press - 2023

Keywords

  • diamene
  • epitaxial graphene
  • hardness
  • SiC
  • Young's modulus

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Chemical Engineering(all)
  • Materials Science(all)
  • Biochemistry, Genetics and Molecular Biology (miscellaneous)
  • Engineering(all)
  • Physics and Astronomy(all)

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