The effect of graphene nanoplatelet thickness on the fracture toughness of Si 3 N 4 composites

Orsolya Tapasztó, Viktor Puchy, Zsolt E. Horváth, Zsolt Fogarassy, Eszter Bódis, Zoltán Károly, Katalin Balázsi, Jan Dusza, Levente Tapasztó

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5 Citations (Scopus)


Si 3 N 4 composites with 3 and 5 wt% of graphene nanoplatelet (GNP) additions were prepared by spark plasma sintering. We used both commercially available GNPs and thinner few-layer graphene nanoplatelets (FL-GNPs) prepared by further exfoliation through ball milling with melamine addition. We found that by employing thinner FL-GNPs as filler material a 100% increase in the fracture toughness of Si 3 N 4 /3 wt% FL-GNP composites (10.5 ± 0.2 MPa m 1/2 ) can be achieved as compared to the monolithic Si 3 N 4 samples (5.1 ± 0.3 MPa m 1/2 ), and 60% increase compared to conventional Si 3 N 4 /3 wt% GNP composites (6.6 ± 0.4 MPa m 1/2 ). For 5 wt% filler content the increase of the fracture toughness was near 50% for both GNP and FL-GNP fillers. The hardness of the composites decreased with increasing GNP content. However, composites reinforced with 5 wt% of FL-GNPs displayed 30% higher Vickers hardness (12.8 ± 0.2 GPa) than their counterparts comprising conventional GNP fillers (9.8 ± 0.2 GPa). We attribute the enhanced mechanical properties obtained with thinner FL-GNPs to their higher aspect ratio leading to a more homogeneous dispersion, higher interface area, as well as smaller pores in the ceramic matrix.

Original languageEnglish
Pages (from-to)6858-6862
Number of pages5
JournalCeramics International
Issue number6
Publication statusPublished - Apr 15 2019



  • Composites
  • Graphene nanoplatelets
  • Silicon nitride
  • Toughening

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Tapasztó, O., Puchy, V., Horváth, Z. E., Fogarassy, Z., Bódis, E., Károly, Z., Balázsi, K., Dusza, J., & Tapasztó, L. (2019). The effect of graphene nanoplatelet thickness on the fracture toughness of Si 3 N 4 composites Ceramics International, 45(6), 6858-6862.