Effect of temperature gradient on the erosion behavior of SiC coating for carbon/carbon composites in a combustion environment

SiC coating with a thickness of 50-70 mu m was prepared on the surface of C/C composites by in-situ reaction method. The SiC coated C/C composites were then tested in a wind tunnel where a temperature gradient from 200 to 1600 degrees C could be obtained to investigate their erosion behavior. The results of wind tunnel test indicated that the service life of C/C composites was prolonged from 0.5 to 44 h after applying the SiC coating. After the wind tunnel test, three typical oxidation morphologies, including glassy SiO2 layer, porous SiO2 layer and clusters of honeycomb-like SiO2 grains, were found on the SiC coated C/C composites. With the decrease of oxidation temperature, the amount of glassy SiO2 declined and the thermal stress increased, which induced the cracking followed by the degradation of the SiC coating. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.