Effect of carbon nanotubes on the toughness, bonding strength and thermal shock resistance of SiC coating for C/C-ZrC-SiC composites

In order to improve the toughness, interface bonding strength and thermal shock resistance of SiC coating for C/C-ZrC-SiC composites, carbon nanotubes (CNTs) were prepared by injection chemical vapor deposition and attempted as the reinforcement materials in the SiC coating. After incorporating CNTs, the hardness and elastic modulus of the SiC coating increased by 26.37% and 28.23%, respectively. The interface bonding strength between SiC coating and C/C-ZrC-SiC composites was enhanced by 53.31%. The mass loss of the SiC coated C/C-ZrC-SiC composites after thermal shock between 1773 K and room temperature for 15 times decreased from 5.98% to 1.98%. The incorporation of CNTs can effectively improve the toughness, interface bonding strength and thermal shock resistance of SiC coating due to the nanoscale toughening mechanism of CNTs by pullout, bridging and crack deflection.