Advanced anti-ablation C/C composites: structural design strategies and future perspective

Carbon fiber reinforced carbon matrix (carbon/carbon, C/C) composites are promising thermal protection candidates for ultra-high temperature applications. However, their high oxidation sensitivity poses a use limitation in ultra-high temperature and high-speed aerobic environments. Matrix modification and coating technology with Si-based or ultra-high temperature ceramics have proved to be highly effective in improving the oxidation and ablation resistance of C/C composites. Nevertheless, challenges persist due to the inherent brittleness and poor thermal conductivity of ceramics, the inability of modified C/C composites to form dense oxide barrier layers, and thermo-physical mismatch issues that lead to crack formation and coating falloff. Thus, the development of high-performance C/C composites is ongoing and a series of advancements have been achieved, focusing on alleviating local overheating and insufficient ablation resistance, while also enhancing the component structural stability. To expedite the development of anti-ablation C/C composites and avoid aimless trial-and-error efforts, this review comprehensively summarizes the latest significant progress and breakthroughs achieved in the area. A brief overview of the structure, fabrication methods and ablation testing techniques of C/C composites is first introduced. The following emphasis is on discussing different structural design strategies on carbon fibers, preforms, matrix carbon, modification and coating methods, aiming to provide insightful design principles and valuable references for future research activities. Finally, the ongoing challenges and research directions in the future of developing high-performance anti-ablation C/C composites, incorporating our insights and perspectives, are discussed.