Graphene & 2D Materials

Graphene-ceramic composites are focusing worldwide attention because they allow to combine some very attractive electrical, thermal and mechanical properties. Among the matrices investigated are Si3N4, TaC, Al2O3, ZrO2-toughened Al2O3, MgO, hydroxyapatite and SiO2, the latter mainly as film. It is acknowledged that one of the main challenges of the field is to develop processing routes ensuring homogeneous dispersion of graphene in the ceramic matrix, without inducing contamination and introducing undesirable structural defects. These routes will be reviewed. Consolidation is performed by several techniques including hot isostatic pressing (HIP) and spark plasma sintering (SPS). One key feature is that the grapheneinduced grain-size refinement of the matrix is to be taken into account when discussing the properties. Results on the electrical, thermal and mechanical properties will be discussed. The proposed mechanical reinforment and toughning mechanisms, such as graphene pullout, crack bridging, crack deflection and crack branching will be presented. When appropriate, a parallel with carbon nanotube-ceramic composites will be made.