Facile preparation of SiC/ZrB2-SiC-Si coatings on Cf/SiC composites for ultrahigh temperature ablation resistance

A slurry method combined with silicon infiltration has good prospects in preparing ZrB 2 -SiC coatings yet remains a great challenge due to the unevenly distributed ZrB 2 and heavily damaged substrate. Here we develop a SiC/ ZrB 2 -SiC-Si bilayer coating on C f /SiC by the slurry method and low-temperature silicon infiltration. The dense SiC inner layer promotes the interfacial bonding and inhibits the inward infiltration of Si; meanwhile, the liquidgas co-existing siliconization restrains the ZrB 2 aggregation and growth. The resultant coating presents high interfacial bonding of 15.6 MPa, can endure 5 ablation cycles for 600 s at 1900 degrees C. Especially, the coated C f /SiC has high strength retention of 97.3 %.