SiC–MoSi2–(Ti0.8Mo0.2)Si2 multi-composition coating for carbon/carbon composites

To protect carbon/carbon (C/C) composites from oxidation, a new type of oxidation protective coating has been produced by a pack cementation technique in an argon atmosphere. XRD and SEM analysis showed that the phases of the composite coating were composed of SiC, MoSi2, and (Ti0.8Mo0.2)Si2. Oxidation test discovered that the weight loss of the SiC coated C/C was up to 11.26% after 5 h oxidation in air at 1773 K and the weight loss of the SiC–MoSi2–(Ti0.8Mo0.2)Si2 coated C/C composites characterized by excellent thermal shock resistance was only 2.18% in the same condition for 49 h. The oxidation of the coated C/C composites was primarily due to the reaction of the C/C matrix and oxygen diffusing through the penetrable cracks in the coating.