Surface modification of carbon/carbon composites and in-situ grown SiC nanowires to enhance the thermal cycling performance of Si-Mo-Cr coating under parallel oxyacetylene torch

• Surface modification of C/C composites and in-situ grown SiC nanowires were combined.
• Bonding strength of Si-Mo-Cr coating was improved by 5.7% and reached 27.8 MPa.
• CTE mismatch between Si-Mo-Cr coating and C/C substrate was alleviated.
• Thermal cycling test was carried out under parallel oxyacetylene flame.
• Thermal stress during high-low temperature cycles was reduced efficiently.

Before the preparation of Si-Mo-Cr coating, blasting treatment of C/C composites and in-situ grown SiC nanowires were performed. Compared with the coated C/C composites without SiC nanowires, the bonding strength of Si-Mo-Cr coating was increased by 5.7%, and the mass loss per unit area was reduced by 46.39% after 30 thermal cycles between 1600 °C and room temperature. The performance enhancement can be attributed to the improved bonding strength and the alleviation of mismatch of thermal expansion coefficient between C/C substrate and Si-Mo-Cr coating, thereby decreasing the thermal stress during thermal cycles between high and low temperatures.