SiC/SiC–YAG–YSZ oxidation protective coatings for carbon/carbon composites

SiC/SiC–YAG–YSZ coatings were prepared by pack cementation, chemical vapor deposition and slurry painting on carbon/carbon (C/C) composites. The microstructures and oxidation behavior of coatings were investigated. The results show that the coatings displayed good oxidation and thermal shock resistance due to a dense glassy layer with silicates formed on the coating of SiC–YAG–YSZ. The weight gain rate of coated C/C composites was 1.77% after oxidation for 150 h at 1773 K. SiC in outer coating can promote the formation of oxygen diffusion barrier and lead to the optimum oxidation resistance for the coatings, compared with YSZ and YAG.

SiC as the major phase in outer coating can promote the formation of oxygen diffusion barrier and lead to the optimum oxidation resistance for the coatings, compared with YSZ and YAG.Figure optionsDownload as PowerPoint slideHighlights
► SiC/SiC–YAG(Y3Al5O12)–YSZ(Y0.16Zr0.92O2.08) coatings were prepared on C/C composites.
► The coatings exhibit good oxidation and thermal shock resistance at 1773 K.
► SiC in outer layer can promote the formation of a dense glassy layer with silicates.