Mechanical and ablation properties of three-dimensional ZrC skeleton reinforced graphite-based composites

Graphite materials are the promising aerospace structural materials owing to their low density, high thermal conductivity and high temperature stability. However, the poor mechanical properties and inferior ablation resistance of graphite materials limits their applications in advanced space vehicles. To address the problem, three-dimensional zirconium carbide (3D ZrC) skeleton reinforced graphite composites (Mesocarbon microbeads, MCMB) were designed and fabricated by the combination of molten salt coating and spark plasma sintering (SPS) route. The effect of ZrC content on the mechanical and ablation properties was investigated in detail. With the ZrC content of 45 vol%, the bending strength and fracture toughness of the MCMB@ZrC composite were 112 MPa and 1.72 MPa·m^1/2, respectively. After ablation at 2.4 MW·m^-2 for 60 s, the MCMB@ZrC composites with 30 vol% ZrC performed the best ablation performance and remained intact after ablation with the linear and mass ablation of 2.13 μm·s^-1 and 4.24 mg·s^-1, respectively. The 3D ZrC skeleton with moderate content provides effective support for the graphite matrix and thermal protection in the ablation process to a certain extent.