Study on the thermal fatigue behavior of SiC coated carbon/carbon composites

A SiC coating was prepared on carbon/carbon (C/C) composites surface by pack cementation and the thermal fatigue behavior of the SiC coated C/C composites was studied. During thermal cycle between 1873 K air and 373 K boiling water, the weight of the SiC coated sample decreased lightly, while the flexural strength was reduced obviously. After thermal cycle for 50 times, the weight loss of the SiC coated sample was 2.76% and the percentage of remaining strength was 74.5%. The decrease of the flexural strength during the thermal cycle was primarily due to the debonding of the fiber-matrix interfaces and the oxidation of the coated samples by oxygen or vapor.