Gradient structured C/C-ZrC-SiC composites with enhanced mechanical and ablation properties

Given the diverse requirements of thermal protection systems for C/C composites, achieving a simultaneous enhancement of ablative and mechanical properties while ensuring lightweight is a great challenge. Recent research has discovered the development of a gradient structure has the potential to achieve multiple performance improvements simultaneously. Herein, we designed gradient C/C-ZrC-SiC composites by reactive melt infiltration and chemical vapor infiltration. The gradient structured C/C-ZrC-SiC composites achieve good shear strength of 62 MPa, revealing an increase of 26.3 % compared to the traditional C/C-ZrC-SiC composites. After ablation at 3000 °C for 60 s, the composites also show good ablation properties with linear and mass ablation rates of 2.37 μm/s and 2.07 mg/s, respectively, which is attributed to the synergistic effect of oxygen resistance of the dense oxide layer and heat transfer of the pyrolytic carbon network in gradient structure.