Effect of LaB6 on the thermal shock property of MoSi2-SiC coating for carbon/carbon composites

► LaB6-MoSi2-SiC and MoSi2-SiC multi-composition coatings were coated on C/C composites by pack cementation. ► The microstructure and thermal shock resistance of both coatings were investigated. ► The addition of LaB6 can increase the compactness, flexural strength and fracture toughness of the MoSi2-SiC coating simultaneously. ► Both coatings bond well with the substrates before and after thermal cycling oxidation between 1773 K and room temperature. ► The LaB6-MoSi2-SiC coated C/C shows better thermal shock resistance than the MoSi2-SiC coated C/C.