SiC-Si coating with micro-pores to protect carbon/carbon composites against oxidation

To improve the oxidation resistance of carbon/carbon (C/C) composites at high temperatures, a SiC-Si coating with micro-pores was prepared by slurry and heat-treatment on the surface of C/C composites with SiC-Si inner coating acquired by pack cementation (PC). The microstructure, phase composition, element distribution, and anti-oxidation properties of the dual-layer SiC-Si coating were investigated. The results show that a SiO2-SiC inlay structure was formed during the oxidation process, due to a large amount of SiO2 rapidly generated by the oxidation of SiC particles in the porous coating. The coating with this structure could inhibit the cracking of SiO2 glass and had a good resistance to oxygen diffusion. Moreover, the crack propagation was blocked by the remaining micro-pores of the coating. The coating could protect C/C composites against oxidation for 846 h only with the mass loss of 0.16 % at 1773 K in air.

Automated summary

The study demonstrated that preparing a SiC-Si coating on the surface of C/C composites can effectively enhance their oxidation resistance at high temperatures. The SiO2-SiC inlay structure in the coating can inhibit cracking and oxygen diffusion, protecting the composites from oxidation.