Convenient Reparation of SiC-Coated C/C Composites by the Slurry Painting Method

SiC-coated C/C composites with mechanical damage were repaired by the heat treatment method and slurry painting-preoxidation. The effects of different process parameters on the microstructure, interface bonding and oxidation resistance of Si-SiC repair coatings at 1773 K for 10 h were studied. The results show that the repair coating is tightly bonded to the original coating and the C/C substrate, and there is no obvious interface. Under the optimal parameters, the weight reduction in the repaired specimen merely amounted to 0.32% subsequent to oxidation at 1773 K for 10 h, and the mass loss was 74.79% lower than that of the damaged specimen, being proximate to that of the intact specimen. The objective of this work lies in achieving a greater density of the coating within the repair zone by manipulating the diverse powder ratios and preoxidation temperatures in the repair slurry, thereby safeguarding the C/C composite material against oxidation during its service. It offers a convenient and highly efficient approach for the repair of coatings with substantial size defects, significantly prolonging the service life of the material.