Carbon fiber reinforced carbon composites are easily oxidized in high temperature environments. Carbon fiber reinforced carbon composites (such as carbon fiber reinforced carbon (Cf/C) and carbon fiber reinforced silicon carbide (Cf/SiC)) are prone to oxidation and ablation in high temperature and oxygen environments, resulting in a significant decrease in the mechanical properties of carbon fiber, limiting its application in high temperature environments.
Antioxidation methods
Selecting suitable carbon fiber: High-quality, high-oxidation-stable carbon fiber is the basis for improving the antioxidant capacity of composite materials.
Surface treatment: Increase surface density and smoothness through chemical vapor deposition, physical vapor deposition, and electrochemical oxidation to reduce the entry of oxygen molecules.
Add antioxidants: Add antioxidants such as aluminum oxide and silicon oxide during the preparation process to improve the antioxidant capacity of composite materials.
Control heat treatment temperature and time: Reasonably control heat treatment temperature and time to avoid oxidation and thermal expansion problems.
Use silica coating: Apply a layer of silica on the surface of the composite material to increase antioxidant capacity and reduce thermal radiation.
Anti-oxidation coating technology: By improving and optimizing the coating preparation process, the coating bonding strength and anti-oxidation ability at ultra-high temperatures are improved. For example, SiC/SiO₂ coating and SiC-ZrO₂-MoSi₂-Ni composite coating are prepared on the surface of carbon fiber using modified sol-gel-emulsion method and composite electroplating method, which significantly improves the anti-oxidation performance.