Impact of metastable graphene-diamond coatings on the fracture toughness of silicon carbide

Martin Rejhon, Václav Dědič, Mykhailo Shestopalov, Jan Kunc, Elisa Riedo

Research output: Contribution to journalArticlepeer-review

Abstract

Silicon carbide has excellent mechanical properties such as high hardness and strength, but its applications for body armor and protective coating solutions are limited by its poor toughness. It has been demonstrated that epitaxial graphene-coated SiC can enhance SiC mechanical properties due to the pressure-activated phase transition into a sp3 diamond structure. Here, we show that atomically thin graphene coatings increase the hardness of SiC even for indentation depths of ∼10 μm. Very importantly, the graphene coating also causes an increase of the fracture toughness by 11% compared to bare SiC, which is in contradiction with the general indirect variation of hardness and fracture toughness. This is explained in terms of the presence of a diamond phase under the indenter while the rest of the coating remains in the ultra-tough graphene phase. This study opens new venues for understanding hardness and toughness in metastable systems and for the applications of graphene-coatings.

Original languageEnglish (US)
JournalNanoscale
DOIs
StateAccepted/In press - 2024

ASJC Scopus subject areas

  • General Materials Science

Fingerprint

Dive into the research topics of 'Impact of metastable graphene-diamond coatings on the fracture toughness of silicon carbide'. Together they form a unique fingerprint.

Cite this