Effect of precoated carbon layer on microstructure and anti-erosion properties of SiC coating for 2D-C/C composites

To improve the erosion resistant of carbon-carbon composites, an SiC coating was synthesized on carbon-carbon composites by the insitu reaction method. They are firstly coated with carbon layer by slurry, and then SiC coatings are obtained by chemical vapor reaction. The effects of precoated carbon layer on the microstructure and anti-erosion properties of SiC-coated C-C composites were studied and characterized. The thickness of the SiC coating increased with the increase in the precoated carbon layer thickness. The different thickness of carbon layer affects hardness of the SiC coatings, resulting in diverse erosion resistance of the coatings. The SiC coating prepared with moderate thickness of precoated carbon layer exhibits the best erosion resistance, and show better resistance at an impact angle of 30 degrees than 90 degrees. The eroded surface revealed that coating cracking and brittle fracture, fiber-matrix debonding, fiber breakage, and material removal, and the additional microcutting and microploughing at oblique impact angle are the major erosion mechanism of SiC coating for C/C composites.