Ablation behavior of (ZrC/SiC)3 alternate coating prepared on sharp leading edge C/C composites by CVD

• A (ZrC/SiC) 3 alternate coating was fabricated on SLE C/C composites via CVD. • The alternate coating can resist the severe ablation induced by sharp shape. • The (ZrC/SiC) 3 alternate coating can relieve the thermal stress during ablation. • The interspaces formed between ZrO 2 layers diminish the rupture risk of oxide layer. • The alternating SiC layers can delay the oxygen erosion of inner coating. A (ZrC/SiC) 3 alternate coating was deposited on sharp leading edge (SLE) C/C composites by chemical vapor deposition (CVD). The ablation behavior was examined via oxyacetylene torch with heat flux of 2.38 MW/m 2 . The results indicated that the alternate coating exhibited great ablation resistance, providing an effective protection for C/C composites. In initial rapid heating stage, the (ZrC/SiC) 3 alternate coating can relieve thermal stress, avoiding the peeling of coating and keeping an intact coating structure. In subsequent ablation, the SiC layers in central region were consumed rapidly, leaving layered interspaces. Three stacked ZrO 2 layers were reserved with the assistance of the release of thermal stress by interspaces, offering a great anti-scouring effect. In transition and border regions, the alternate SiC layers can delay oxygen erosion of inner coating and C/C substrate by the formation of SiO 2 . It is believed that the results would be helpful for the design and application of anti-ablation coatings on SLE C/C composites.