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

Graphite materials are 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 limit their application in advanced space vehicles. To address this problem, three-dimensional zirconium carbide (3D ZrC) skeleton-reinforced graphite composites (mesocarbon microbeads, MCMBs) were designed and fabricated by combination of molten salt coating and spark plasma sintering (SPS). The effects of ZrC content on the mechanical and ablation properties were 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·m1/2, respectively. After ablation at 2.4 MW·m−2 for 60 s, the MCMB@ZrC composites with 30 vol% ZrC exhibited the best ablation performance and remained intact after ablation, with linear and mass ablation rates 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 during the ablation process to a certain extent.