Microstructure and static oxidation performance of ZrB₂-SiC/(C/C) composite coating

The ZrB₂-SiC composite coatings were prepared on C/C composites by slurry painting. The phase composition and microstructure of the as-prepared ZrB₂-SiC/(C/C) composites were analyzed by XRD spectroscopy and SEM, and the static oxidation behavior at 1 200℃ and 1 500℃ were also investigated. The results show that the ZrB₂-SiC coatings are compact and uniform without obvious pores and cracks. After static oxidizing at 1 200℃ for 60 min, the mass loss rate of the as-prepared ZrB₂-SiC/(C/C) composites is only about 2.4%. At 1 500℃, the mass loss rate increases to about 15%, but it is still lower than that of C/C composites without anti-oxidation coatings(~35%). In the static oxidation process, the significantly improved oxidation resistance of the as-prepared ZrB₂-SiC/(C/C) composites is attributed to the generated glassy SiO₂ film containing high melting point particles such as ZrO₂.