Enhanced oxidation resistance of CrSi2-SiC ceramic coatings on SiC coated C/C composites via SiC nanowires reinforcement

A unique bead-chain-like SiC nanowires (SiCnws) morphology was successfully synthesized via an aerogel carbothermal reduction method. Microstructural analysis revealed that the SiC chain display diameters ranging from 100 to 200 nm, while the SiO2 bead exceed 1 μm in diameter. A SiCnws reinforced CrSi2-SiC/SiC coating was prepared on C/C composites by a two-step pack cementation. Comparative analysis revealed that SiCnws-reinforced coating exhibited better densification with lesser cracks and pores. Isothermal oxidation tests at 1773 K in static air demonstrated exceptional performance: the SiCnws-reinforced coating showed only 14.98% mass loss after 30 h, while the unreinforced coating suffered 36.53% mass loss after 14 h. XRD/SEM characterization confirmed that SiCnws enhanced structural integrity by promoting the formation of a continuous SiO2-Cr2O3 glassy layer during oxidation, while mitigating crack propagation through pinning and bridging effects.