Synthesis and properties of bulk graphene nanoplatelets consolidated by spark plasma sintering

Graphene nanoplatelets (GNPs) are consolidated as a bulk structure by spark plasma sintering (SPS) to study the feasibility of its structure retention at extreme processing conditions. Structural characterization of the sintered GNP pellet is performed using Raman spectroscopy and scanning electron microscopy. Mechanical and tribological properties are evaluated through nanoindentation and ball-on-disk tribometer. GNPs survived the SPS processing at an extreme temperature of 1850 °C and a pressure of 80 MPa with minimal damage to the structure. Energy dissipation mechanisms are observed in the form of multiple bending at sharp angles and sliding of the platelets, which could provide effective toughening mechanisms to ceramic matrices. Tribological studies suggest that GNP shear off and weld at higher load and provides a lubricating effect. Our study shows the potential for GNPs to be successfully used as a reinforcing and lubricating phase in ceramic matrix composites synthesized by SPS.