Effects of hypervelocity impact on ablation behavior of SiC coated C/C composites

SiC coated C/C (SiC-C/C) composites were designed to determine effects of hypervelocity impact on ablation behavior of coated carbon/carbon (C/C) composites. They were impacted at 2 km/s and 3 km/s by steel projectiles driven by solid explosive of pentaerythritol tetranitrate and then ablated by oxyacetylene torch for 100 s at 2500 °C. Results showed that ablation areas, the integrity of ablated boundary and ablation rates of all samples increased with the increase of impact velocity. Mass ablation rates of SiC-C/C composites were lower than those of C/C composites under the same test condition. On the contrary, linear ablation rates of SiC-C/C composites were higher than those of C/C composites after the same impact tests. The difference was attributed to the interfaces between SiC coatings and matrix C/C composite. These results demonstrated that morphology of interfaces between coatings and matrix C/C composite was one major factor for the usage of coated C/C composites and could affect the service time of structures with impact damages in high temperature environments.