ZrO2 Short-Fiber-reinforced Oxide Scale Enabling Superior Cyclic Ablation Resistance in C/C–ZrC–SiC Composites Prepared by Reaction Melt Infiltration

Resistance to cyclic ablation is critical for thermal protection system of reusable high-speed vehicles. To address the spallation problem of the oxide scale formed on UHTC-modified C/C composites during cyclic ablation, C/C-ZrC-SiC composites with a ZrO2 short-fiber-reinforced oxide scale (CZS-FOS) were fabricated via reaction melt infiltration (RMI). The stability of the oxide scale under high-temperature scouring conditions was evaluated using an oxyacetylene flame with a heat flux of 4.2 MW/m2. Results demonstrate that CZS-FOS exhibits superior cyclic ablation resistance. Microstructural analyses revealed that a "skeleton structure" oxide scale incorporating in-situ-formed ZrO2 short fibers effectively inhibits the crack propagation and oxide scale spallation, thereby protecting the composites from further ablation. By constructing such an oxide-fiber-reinforced oxide scale, this work provides an effective approach to extend the cyclic service life of UHTC-modified C/C composites in extreme environments.