Ablation and compression properties of reusable needle-punched carbon/carbon composites soaked in seawater: Experimental investigation

Needle-punched carbon/carbon (NP C/C) composites are widely used in rocket-engine nozzles and re-entry vehicles for their high strength, low weight, and thermal stability. Due to cost considerations and strategic defense requirements, the launch and recovery of marine platforms have gradually developed. This study experimentally investigates the combined effects of saltwater immersion and ablation on reusable NP C/C composites. Saltwater introduces chloride ions and salt crystals into the porous matrix, promoting the development of microcracks and increasing porosity. Compressive properties degrade significantly due to fiber-matrix debonding and interface weakening, while increased fracture strain indicates damage accumulation. The chemical corrosion mechanism preferentially damages the fiber/matrix interface, leading to rapid deterioration of strength and modulus. The findings reveal a synergistic degradation mechanism driven by physical and chemical corrosion processes, emphasizing the urgent need for enhanced protective strategies to ensure the long-term reliability of NP C/C composites in harsh marine and aerospace environments.