The effect of graphene nanoplatelet thickness on the fracture toughness of Si3N4 composites. Issue 6 (15th April 2019)

• Record Type: Journal Article
• Authors: Tapasztó, Orsolya; Puchy, Viktor; Horváth, Zsolt E.; Fogarassy, Zsolt; Bódis, Eszter; Károly, Zoltán; Balázsi, Katalin; Dusza, Jan; Tapasztó, Levente
• Is Part Of: Ceramics international. Volume 45:Issue 6(2019)
• Page Start: 6858
• Page End: 6862
• Publication Date: 2019-04-15
• Subjects: Silicon nitride -- Composites -- Graphene nanoplatelets -- Toughening; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2018.12.180
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Si3 N4 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 Si3 N4 /3 wt% FL-GNP composites (10.5 ± 0.2 MPa m 1/2 ) can be achieved as compared to the monolithic Si3 N4 samples (5.1 ± 0.3 MPa m 1/2 ), and 60% increase compared to conventional Si3 N4 /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.