Toughening in graphene ceramic composites

Luke S. Walker, Victoria R. Marotto, Mohammad A. Rafiee, Nikhil Koratkar, Erica L. Corral

Research output: Contribution to journalArticlepeer-review

608 Scopus citations


The majority of work in graphene nanocomposites has focused on polymer matrices. Here we report for the first time the use of graphene to enhance the toughness of bulk silicon nitride ceramics. Ceramics are ideally suited for high-temperature applications but suffer from poor toughness. Our approach uses graphene platelets (GPL) that are homogeneously dispersed with silicon nitride particles and densified, at ∼1650 °C, using spark plasma sintering. The sintering parameters are selected to enable the GPL to survive the harsh processing environment, as confirmed by Raman spectroscopy. We find that the ceramic's fracture toughness increases by up to ∼235% (from ∼2.8 to ∼6.6 MPa·m1/2) at ∼1.5% GPL volume fraction. Most interestingly, novel toughening mechanisms were observed that show GPL wrapping and anchoring themselves around individual ceramic grains to resist sheet pullout. The resulting cage-like graphene structures that encapsulate the individual grains were observed to deflect propagating cracks in not just two but three dimensions.

Original languageEnglish (US)
Pages (from-to)3182-3190
Number of pages9
JournalACS Nano
Issue number4
StatePublished - Apr 26 2011


  • ceramics
  • fracture toughness
  • graphene
  • nanocomposites
  • silicon nitride

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


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