Fabrication of porous SiC nanostructured coatings on C/C composite by laser chemical vapor deposition for improving the thermal shock resistance

Recently, fabricating one-dimensional (1D) nanomaterials on C/C composite has been recognized effective to improve the thermal shock resistance of the coated composites. However, the remaining metal catalyst in CVD process and the week bond of 1D nanomaterials with substrate limit the strengthening effect. Herein, laser chemical vapor deposition (LCVD) was proposed for fabricating porous SiC nanostructured coating on C/C composite without metal catalyst. The laser heating resulted in a temperature gradient between the top and bottom of the coating, providing an external driving force for the vertical growth of whiskers with side-branches, forming a porous network nanostructure. The porous nanostructure was beneficial to reduce CTE and effectively relieve thermal stress. After 10 times of thermal shock test from RT to 1723 K, the porous SiC nanostructured coating remained intact. This work provides a novel methodology to produce functional coating on C/C composite with outstanding thermal shock resistance.