Oxidation pre-treatment and electrophoretic deposition of SiC nanowires to improve the thermal shock resistance of SiC coating for C/C composites

To improve the thermal shock resistance of SiC coating for carbon/carbon composites (C/Cs) prepared by chemical vapor deposition (CVD), mild oxidation of C/C substrate and electrophoretic deposition (EPD) of SiC nanowires were used before CVD, aiming to modify the mechanical properties of SiC coating. In comparison to the pristine one, the modified SiC coating shows 73.1% and 93.5% improvements respectively in fracture toughness and adhesion with C/Cs, which endows the coating with fewer and smaller cracks and better thermal shock resistance between 1200°C and room temperature. It has been also demonstrated that the combined pre-treatments can increase the thermal shock performance of CVD SiC coating better than individual one, which paves a way for greatly increasing the efficiency of SiC coating in protecting C/Cs against oxidation consumption at intermediate temperatures (800-1200°C).