Design and preparation of graphene-modified SiC whisker-based porous structure on C/C composite surface and its brazing to copper

Porous graphene surface-optimized SiC nanowhiskers were introduced at the joining surface of C/C composites using a two-step method of electrophoretic deposition and chemical vapor deposition processes, alleviating thermal stress and thermal damage at the interface near the C/C side during the brazing process and improving the strength of the C/C–Cu joints. The results showed that the prefabricated structure significantly improved the wettability of the AgCuTi filler on the C/C surface. The development of a continuous reaction layer with a gradient distribution in the coefficient of thermal expansion, along with refined metal matrix, contributed to reducing residual thermal stress at the interface. In addition, the gradient layer prevented the excessive infiltration of metal filler on the C/C side and relieved structural damage to the carbon matrix. The average shear strength of the surface-modified C/C–Cu joints was approximately 56.2 MPa, which was 78.4 % higher than that of the original joints.