Mechanical properties, thermophysical properties, and long-term ablation behaviours of C/C–ZrC– ZrB2– W–Cu composites

Spacecraft thermal protection materials need to survive long-term exposure to oxygen-containing environments at 2400 °C. In this study, a high-density and low-porosity metal-ceramic-modified composite was prepared at a low temperature (1500 °C) in the presence of W and Cu using combined slurry brushing and reactive melt infiltration methods. An investigation of the composite formation mechanism and the effects of W and Cu indicated that W and ZrB 2 were formed via dissolution-precipitation and the external diffusion of C and B, respectively. The low reaction temperature and the metallic phases significantly improved the mechanical properties, thermophysical properties, and long-term ablation behaviours of C/C–ZrC–ZrB 2 –W–Cu. Compared to traditional C/C–ZrC, the flexural strength and fracture toughness of the composite increased by 71.56 % and 90.05 % to 345.95 MPa and 14.52 MPa m 1/2 , respectively, and the thermal conductivity increased by 174.93 % to 59.11 W/m·K. In addition, W and Cu effectively lowered the surface temperature by nearly 250 °C during 300 s ablation, and the mass and line ablation rates decreased to −0.272 mg/s and −0.247 μm/s, respectively.