Research progress in chemical vapor deposition for high-temperature anti-oxidation/ablation coatings on thermal structural composites

Carbon/carbon(C/C) and carbon/silicon carbide (C/SiC) composites reinforced with carbon fiber have become a promising thermal structural material in aerospace field due to their excellent properties. However, their highly susceptible to destructive oxidation and ablation at high temperatures, causing the rapid failure and compromising their distinctive structural advantages. To address these challenges, the implementation of high-temperature anti-oxidation/ablation (HTA) coating is considered as primary solution to mitigate the chemical and physical degradation of high strength thermal structural composites in high temperature environments. Moreover, chemical vapor deposition (CVD) has become one of the most important technologies for the preparation of HTA coating due to its capability to synthesize compact microstructures and uniformly coat intricate components. Herein, the study begins with the CVD process for the various types of HTA coating, the latest development of Si-based ceramic coatings and UHTC coatings (carbides, borides and partial nitrides) were outlined, including their preparation procedures and anti-oxidation/ablation properties. Furthermore, the current composition and structural design strategies for improving the mechanical and anti-oxidation/ablation performance of the coating were summarized, including constructing multi-phase/solid solution coatings, toughening coatings by nanowires and designing multi-layer structure. Finally, the current challenges and future development directions of CVD technology in the field of coating preparation were proposed. This review aims to offer valuable insights for researchers and engineers working in the fields of HTA coating and CVD technology.