Microstructure and anti-oxidation property of CrSi2–SiC coating for carbon/carbon composites

Abstract: To protect carbon/carbon (C/C) composites from oxidation, a new type of oxidation protective coating has been produced by a two-step pack cementation technique. XRD and SEM analysis show, the coating obtained by the first step pack cementation was a porous β-SiC structure, and a new phase of CrSi2 was generated in the porous SiC coating after heat-treatment according to the second step pack cementation process. Oxidation test shows that, the weight loss of the SiC coated C/C is up to 11.26% after 5h oxidation in air at 1773K, and the weight loss of the CrSi2–SiC coated C/C composites is only 4.15% after oxidation in air at 1773K for 34h. The oxidation of C/C composites was primarily due to the reaction of C/C matrix and oxygen diffusing through the penetrable cracks in the coating. [Copyright &y& Elsevier]