Anti-ablation property of SiC coating on C/C composites at high speed

To protect carbon/carbon (C/C) composites against ablation at high speed airflow, SiC coating was prepared on the surface of C/C composites by low pressure chemical vapor deposition. The microstructure of the as-received coating was analyzed by XRD and SEM. The binding force between the coating and composites was tested by scratch tester. The ablation behaviors of the coated samples at high speed airflow were studied. The results show that the as-received SiC coating possesses a crack-free structure. The binding force is 5 N, which is weak between the coating and composites. After ablation for 600 s, most region of the coating remain intact, the coating where the airflow scoured the most severely is damaged. Mechanical denudation is the main reason of the coating's failure at high speed airflow.