To investigate the effect of ZrC on the ablative properties of C/SiC composites in a high-temperature environment, the oxidative ablation of C/SiC and C/SiC-ZrC composites at high-temperatures was examined through ablation tests. In this study, two ceramic matrix composites, C/SiC and C/SiC-ZrC, were prepared by chemical vapor deposition and precursor impregnation pyrolysis. The ablation properties of the materials were tested and analyzed using an oxyacetylene flame to simulate a high-temperature environment. The results revealed that the line ablation rate of C/SiC-ZrC was 8.48% and 20.81% lower than that of C/SiC at 30 s and 60 s, respectively. At the same ablation time, the depth of the crater resulting from erosion of the C/SiC material by the high-temperature airflow was deeper than that of C/SiC-ZrC. The traces of the fibers subjected to erosion were more prominent. In a longitudinal comparison, the mass ablation rate of C/SiC-ZrC material decreased with the increase in time, while the line ablation rate initially increased rapidly and then decreased. From 30 s to 90 s of ablation, the line ablation rate and mass ablation rate decreased by 55.62% and 89.5%, respectively. The overall trend for both rates was a decrease with the increase in time. Under the same ablation time, the ablation rate of C/SiC-ZrC was generally lower than that of C/SiC. This is because the generated molten ZrO₂ was more viscous and denser than SiO₂, effectively blocking oxidizing gases from penetrating the interior of the material. The molten ZrO₂ provided better protection for the substrate in the high-temperature environment.

To reveal the ablation performance of C/SiC-ZrC composites under different ablation modes, C/SiC-ZrC composites were prepared using chemical vapor deposition, precursor infiltration, and pyrolysis. Single ablation and cyclic ablation tests were conducted on the C/SiC-ZrC composites using an oxyacetylene flame, in order to obtain ablation parameters, as well as macroscopic and microscopic ablation morphology for the different ablation modes. The results show that the linear ablation rate and mass ablation rate of different ablation modes decrease with increasing time. The linear ablation rate and mass ablation rate of cyclic ablation are 12% and 24.2% lower than those of single ablation. Within the same ablation time, the C/SiC-ZrC composites subjected to cyclic ablation exhibit shallower and more evenly distributed pits, caused by high-temperature airflow ablation. The material surface has a white oxide layer composed of SiO2 and ZrO2, and the carbon fibers inside are wrapped by oxide particles, enhancing the ablation resistance of C/SiC-ZrC composites.