MoSi2-IMPROVED SiC COATING TO PROTECT CARBON/CARBON COMPOSITES AGAINST OXIDATION

To improve the oxidation protective ability of SiC coating for carbon/carbon (C/C) composites, MoSi2 was introduced in the SiC coating by infiltration technique. XRD and SEM analysis show that the SiC coating obtained by pack cementation is a porous structure with a thickness of about 60–100 μm. After infiltration treatment, MoSi2 was filled in the holes of the porous SiC-coating, and the as-received coating becomes dense without through-thickness crack. Oxidation test shows that, the weight loss of the SiC-coated C/C is up to 9.23% after 53 h oxidation in air at 1773 K, while the weight loss of the MoSi2-improved SiC-coated C/C composites is only 0.73% after oxidation for 265 h. The oxidation of C/C composites is primarily due to the formation of the penetration cracks and the holes on the glass layer.