Preparation and oxidation kinetics of SiC/ZrO₂-SiO₂ oxidation protective coating for carbon-carbon composites

SiC internal bonding layer was prepared by pack cementation, and later gradient ZrO₂-SiO₂ coating was applied on the SiC coating surface using a sol-gel process. The as-prepared multi-coating was characterized by XRD and SEM analyses. The oxidation kinetics of the coated C/C was also investigated under different temperature. The results showed that the multi-coating was composed by SiC, SiO₂, ZrO₂ and ZrSiO₄; the holes of SiC coating were filled with ZrO ₂-SiO₂ layer; the oxidation resistance of the coated C/C was improved with the increase of the gradient ZrO₂-SiO₂ layer; the multi-coating could effectively protecting C/C composites from oxidation for 10h at 1500°C, and the weight loss of the coating is less than 2.0%; the oxidation activation energy of the coated C/C is 88.2KJ/mol.