Research Progress in Nanotoughening of Matrix and Surface Coatings for Carbon/Carbon Composites

ABSTRACT

Carbon/carbon (C/C) composites are promising high‐temperature structural materials because of their high specific strength, thermal conductivity, and thermal stability. However, severe oxidation above 400°C significantly degrades their performance. Although oxidation‐resistant coatings can effectively protect C/C composites, thermal expansion mismatch between the coatings and the substrates often causes cracking and coating failure. To address this issue, nanotoughening strategies based on coating reinforcement and matrix modification have been extensively developed. Nanomaterials such as silicon carbide (SiC) nanowires, HfC nanowires (HfCNWs), and carbon nanotubes (CNTs) enhance toughness through crack bridging, crack deflection, and interfacial strengthening. This review summarizes recent progress in the application of these nanomaterials to coating toughening and matrix modification of C/C composites, focusing on fabrication methods, toughening mechanisms, and performance improvements. The relationships among reinforcement design, interfacial regulation, and oxidation resistance, thermal shock resistance, and ablation resistance are discussed, providing guidance for the development of advanced ceramic coatings and high‐temperature structural materials.