Preparing the SiC coated C/C composites with excellent mechanical and antioxidative properties using a buffer layer

The preparation of SiC coating on C/C composites via a pack cementation method would cause serious mechanical damage to C/C substrate due to the siliconization corrosion by molten silicon during the ultra-high-temperature preparation process (2173-2373 K). In order to prepare SiC coated C/C composites with excellent mechanical and antioxidative properties, we applied a buffer layer on the surface of C/C to inhibit siliconization corrosion and densify coating. Results showed that the siliconized area ratio of the C/C substrate was decreased from 60.9% to 24.8%, and its bending strength was increased from 36.9 MPa to 60.6 MPa. Moreover, the mass loss of the modified SiC coated C/C sample has reduced by ~4.14 times after oxidation for 144 h in air at 1773 K and decreased from 2.44% to -0.15% after suffering 50 thermal cycles between room temperature and 1773 K.