A ZrB₂–SiC/SiC oxidation protective dual-layer coating for carbon/carbon composites

In order to improve the oxidation resistance of C/C composites, a ZrB₂–SiC/SiC oxidation protective dual-layer coating was prepared by a pack cementation combined with the slurry paste method. The phase and microstructure of the coating were characterised by X-ray diffraction, scanning electron microscope and energy-dispersive spectrometer analyses. The anti-oxidation and thermal shock resistance of the coating were also investigated. It was found that the ZrB₂–SiC/SiC coating could effectively improve the oxidation resistance of the C/C composites. The weight loss of the coated samples was only 1.8% after oxidation at 1773 K for 18 h in air. The coating endured 20 thermal shock cycles between 1773 K and room temperature with only 4.6% weight loss.